Cummins/Onan 5.5 HGJAE troubleshooting: 197 fault codes and 27 symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan 5.5 HGJAE — full specs, parts & maintenance.
All Cummins/Onan fault codes →
| Code | Meaning | Cause | Remedy |
|---|---|---|---|
| 2 | Low oil pressure fault | Low/high oil level, faulty switch, faulty oil pressure relief valve, fault oil pump | Verify that Last Fault is FC 2: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure oil level: add or drain oil as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Measure continuity change across start/stop switch between rest and under simulated pressure: replace switch as necessary; HGJAB, C – Measure continuity between ground and P1–13: repair or replace harness as necessary. HGJAA, D, E, F – Measure continuity between ground and P1–6: repair or replace harness as necessary; Measure oil pressure with mechanical gauge: repair or replace relief valve and oil pump as necessary |
| 3 | Service check fault | Any Two-Digit Fault Code | Verify that Last Fault is FC 3: Yes, continue diagnosis; No, troubleshoot actual last fault; While LED is flashing three times press stop once (1 second duration): trouble shoot Two-Digit Fault Code |
| 4 | Overcrank | Faulty switch, faulty external start command, fuel supply, air fuel mixture, exhaust system, wire connections, starter, ignition system | Verify that Last Fault is FC 4: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure for continuity change across start/stop switch between neutral and start position at switches and P1 connector: replace switches as necessary or disconnect external start device if so equipped; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Verify engine rotation manually: repair engine damage as necessary; Measure DC voltage at starter during start attempt: repair wire connections, replace start solenoid and starter as necessary; Check air filter cleanliness; replace air filter as necessary; Check for blocked or damaged exhaust system: repair or replace exhaust components as necessary; All Gasoline Models: Vapor lock may occur in high ambient temperatures: operate in ambients at less than 120°F; verify proper installation to prevent air recirculation; correct as necessary. Measure steady DC voltage at fuel pump while genset is cranking: repair wiring as necessary. Try to start genset on shop fuel supply: verify tank level and fuel line condition in vehicle; All Gasoline Carburetor Models: Verify carburetor altitude setting: readjust as necessary. Verify choke operation, setting, linkage, vacuum pull off assembly and sustain valve: readjust, repair or replace as necessary. Measure fuel pump pressure/flow: replace fuel filter or fuel pump as necessary. Inspect carburetor butterfly for binding: replace carburetor as necessary; All Gasoline EFI Models: Inspect throttle body for binding or damage: replace as necessary. Measure fuel pump pressure/flow: replace fuel filter, pressure regulator or fuel pump as necessary; Propane Models: When ambient temperatures are less than 40°F vapor-withdrawal Propane tanks should be at least half full to provide proper vaporization rate. Propane having more than 2.5 percent Butane will not vaporize in ambients at less than 32°F; use HD–5 grade Propane. Measure steady DC voltage at fuel solenoid while genset is running; repair wiring as necessary. Verify clear vent hose. Run genset on shop fuel supply; verify tank level and fuel line condition in vehicle. Check genset fuel lines for damage: replace fuel line as required. Measure regulator lock off pressure; Check governor, actuator, linkage and spring for debris, damage and looseness: readjust and repair as necessary; Verify that spark plug cables are secure on spark plugs |
| 13 | AC voltage S1–S2 less than 108 VAC for 5 continuous seconds | Genset loads, Inverter/Charger, wire connections, generator drive system, windings, AC sense transformer, windings | Verify that Last Fault is FC 13: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure AC voltage; Measure AC voltage in and out of sense transformer (if so equipped): repair wire connection, replace sense transformer as necessary; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response: repair damaged generator drive system as necessary; Cycle loads to determine if a particular load will cause fault: diagnose faulty load as necessary; Determine battery charge rate (typical default is 80 percent): if adjustable reduce to 30 percent; Verify balanced loads in 120/240 VAC applications: balance loads within 10 percent line–to–line as required; HGJAD only – Run genset in Engine Run Only mode and externally excite field F1–F2 with 12 VDC or 24 VDC and measure main and quadrature winding AC output; Non EFI – If the genset will not stay running measure genset frequency, quadrature winding and main winding voltages using Break-Out Tool 420–0603 and Instruction Sheet R1098; Remove connector P1 from control and re-install and try to start genset: inspect, repair or replace P1 connector pins as necessary; Measure field, quadrature and main winding resistance: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to ground: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to each other: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Check brush alignment per PSB-682a; Dealers contact Distributor for technical support, Distributors contact factory for technical support |
| 14 | Overfrequency | Genset loads, Inverter/Charger, engine governor function, fuel supply, air fuel mixture, exhaust system, choke, demand regulator, carburetor, generator drive system, generator windings, ignition, wire connections | Verify that Last Fault is FC 14: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure AC current while running genset with vehicle loads: identify faulty or short cycling loads; Determine battery charge rate (typical default is 80 percent): if adjustable reduce to 30 percent; Measure genset load capability with shop load bank (derate for altitude and temperature as necessary); Measure genset frequency and droop while running; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response: repair damaged generator drive system as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Check governor, actuator, linkage and spring for debris, damage and looseness: readjust and repair as necessary; Measure field, quadrature and main winding resistance: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to ground: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to each other: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Check brush alignment per PSB-682a; Verify that spark plug cables are secure on spark plugs: reconnect or replace as necessary; Inspect ignition kill leads in harness and at connector P1: repair or replace lead, terminal or pins as necessary; Test Magnetos: Disconnect Connector P1. Connect positive(+) meter lead to chassis ground. HGJAA, D, E, F – Measure continuity to negative lead at pin P1–4 and P1–5: replace magnetos as necessary. HGJAB, C – Measure continuity to negative lead at pin P1–15 and P1–20: replace magnetos as necessary; Measure spark plug gap: set gap or replace spark plugs as necessary; Verify ignition spark condition; Inspect spark plug lead, kill lead terminal at magneto and measure magneto air gap: replace terminals, set gap or replace magnetos as necessary; Measure temperature of air intake and temperature rise across genset; remove blockage or prevent air recirculation; Dealers contact Distributor for technical support, Distributors contact factory for technical support |
| 17 | Fuel pump fault | Wire connections, harness leads, faulty fuel pump | Verify that Last Fault is FC 17: Yes, continue diagnosis; No, troubleshoot actual last fault; Verify fuel pump operation in prime mode, if pump operates fault condition has been cleared verify harness connections, no further troubleshooting; HGJAA, D Check continuity across fuse F1; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector, prime genset to verify pump operation and test run genset for fault occurrence; Measure continuity between E2 fuel pump leads; replace terminals or fuel pump as necessary; Measure voltage between fuel pump E2 + and ground while priming; replace terminals, harness leads or control as necessary |
| 19 | Governor actuator (EFI only) | Wire connections, P1–17, governor actuator | Verify that Last Fault is FC 19: Yes, continue diagnosis; No, troubleshoot actual last fault; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; P1–17 open to ground on EFI Models: ground lead as required for carburetor configuration; Verify actuator function by applying DC voltage to terminals: replace actuator as necessary; Measure resistance between actuator terminals; repair or replace connections as necessary, replace governor actuator; Measure continuity between P1–28 and actuator lead; repair or replace terminals and leads as necessary; Measure DC voltage at actuator while starting: replace controller as necessary |
| 22 | Governor actuator overload (EFI only) | Genset loads, Inverter/Charger, wire connections, fuel supply, air fuel mixture, exhaust system, governor actuator, ignition system | Verify that Last Fault is FC 22: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure AC current while running genset with vehicle loads: identify faulty or short cycling loads or reduce vehicle loads as necessary; Determine battery charge rate (typical default is 80 percent): if adjustable reduce to 30 percent; Measure genset load capability with shop load bank (derate for altitude and temperature as necessary); Measure AC frequency and droop while running; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response: repair damaged generator drive system as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Check air filter cleanliness; replace air filter as necessary; Check intake manifold and gaskets for air leaks: tighten fasteners and replace gaskets and manifold as necessary; Check for blocked or damaged exhaust system: repair or replace exhaust components as necessary; Measure fuel pump pressure/flow: replace fuel filter, pressure regulator or fuel pump as necessary; Verify actuator function by applying DC voltage to terminals: replace actuator as necessary; Check throttle body for binding; inspect spring for dirt and debris: clean spring, replace throttle body as necessary; Verify that spark plug cables are secure on spark plugs: reconnect or replace as necessary; Inspect ignition kill leads in harness and at connector P1: repair or replace lead, terminal or pins as necessary; Test Magnetos: Disconnect Connector P1. Connect positive(+) meter lead to chassis ground. HGJAA, D, E, F – Measure continuity to negative lead at pin P1–4 and P1–5: replace magnetos as necessary. HGJAB, C – Measure continuity to negative lead at pin P1–15 and P1–20: replace magnetos as necessary; Measure spark plug gap: set gap or replace spark plugs as necessary; Verify ignition spark condition; Inspect spark plug cables, kill lead terminal at magneto and measure magneto air gap: replace terminals, set gap or replace magnetos as necessary; Dealers contact Distributor for technical support, Distributors contact factory for technical support |
| 23 | Oil pressure switch fault | Wire connections, faulty switch | |
| 29 | High battery voltage | Incorrect battery configuration, wire damage, faulty charger, control | Verify that Last Fault is FC 29: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure DC voltage at battery, genset and connector P1: reconnect battery or repair wiring as necessary; Measure DC voltage with battery charger on: reduce boost charge rate or diagnose faulty charger as necessary; If genset shares batteries with propulsion engine, check for fault using shop battery (voltage spike may cause fault): diagnose fault or voltage spikes from propulsion engine charging system; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: replace controller |
| 31 | Overspeed fault (HGJAD, E, F models only) | Engine governor function, fuel supply, air fuel mixture, exhaust system, choke, demand regulator, carburetor, generator drive system, ignition, wire connections | Verify that Last Fault is FC 31: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure genset frequency and droop while running; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response: repair damaged generator drive system as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Inspect spark plug lead, kill lead terminal at magneto and measure magneto air gap: replace terminals, set gap or replace magnetos as necessary; Measure temperature of air intake and temperature rise across genset; remove blockage or prevent air recirculation; Dealers contact Distributor for technical support, Distributors contact factory for technical support |
| 33 | Fault Code 33 | Fault Code 3 interpreted as a non-assigned Fault Code 33 | Verify that Last Fault is FC 3 Yes, continue diagnosis; No, troubleshoot actual last fault; While LED is flashing three times press stop once (1 second duration): trouble shoot Two-Digit Fault Code |
| 35 | Control card failure | Faulty program | Verify that Last Fault is FC 35: Yes, continue diagnosis; No, troubleshoot actual last fault; Replace control |
| 36 | Genset stopped without fault condition | Auto Gen Start (AGS), fuel supply, air fuel mixture, exhaust system, loads, Inverter/Charger, choke, demand regulator, carburetor, generator drive system, generator windings, ignition, wire connections | Verify that Last Fault is FC 36: Yes, continue diagnosis; No, troubleshoot actual last fault; Verify whether AGS stopped genset: Yes, disable AGS or explain AGS function to customer (see PSB-666); No, continue diagnosis; Verify engine rotation manually: repair engine damage as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Check air filter cleanliness; replace air filter as necessary; Check for blocked or damaged exhaust system: repair or replace exhaust components as necessary; Measure AC current while running genset with vehicle loads: identify faulty or short cycling loads; Determine battery charge rate (typical default is 80 percent): if adjustable reduce to 30 percent; Measure genset load capability with shop load bank; HGJAD only – Run genset in Engine Run Only and externally excite field F1–F2 with 12 VDC or 24 VDC and measure main and quadrature winding AC output; Non EFI – Verify genset operation and outputs with Break-Out Tool 420–0603 and Instruction Sheet R1098; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response: repair damaged generator drive system as necessary; All Gasoline Models: Vapor lock may occur in high ambient temperatures: operate in ambients at less than 120°F; verify proper installation to prevent air recirculation; correct as necessary; Inspect throttle body for binding or damage: replace as necessary. Measure fuel pump pressure/flow: replace fuel filter, pressure regulator or fuel pump as necessary; Propane Models: When ambient temperatures are less than 40°F vapor-withdrawal Propane tanks should be at least half full to provide proper vaporization rate. Propane having more than 2.5 percent Butane will not vaporize in ambients at less than 32°F; use HD–5 grade Propane. Measure steady DC voltage at fuel solenoid while genset is running; repair wiring as necessary. Verify clear vent hose. Run genset on shop fuel supply; verify tank level and fuel line condition in vehicle. Check genset fuel lines for damage: replace fuel line as required. Measure regulator lock off pressure; Check governor, actuator, linkage and spring for debris, damage and looseness: readjust and repair as necessary; HGJAD only – Run genset in Engine Run Only and externally excite field F1–F2 with 12 VDC or 24 VDC and measure main and quadrature winding AC output; Non EFI – If the genset will not stay running measure genset frequency, quadrature winding and main winding voltages using Break-Out Tool 420–0603 and Instruction Sheet R1098; Remove connector P1 from control and re-install and try to start genset: inspect, repair or replace P1 connector pins as necessary; Measure field, quadrature and main winding resistance: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to ground: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to each other: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Check brush alignment per PSB-682a; Measure temperature of air intake and temperature rise across genset; remove blockage or prevent air recirculation; Dealers contact Distributor for technical support, Distributors contact factory for technical support |
| 42 | Processor fault | Faulty program | Verify that Last Fault is FC 42: Yes, continue diagnosis; No, troubleshoot actual last fault; Replace control |
| 43 | Processor fault | Faulty program | Verify that Last Fault is FC 43: Yes, continue diagnosis; No, troubleshoot actual last fault; Replace control |
| 45 | Speed sense fault | Auto Gen Start (AGS), fuel supply, air fuel mixture, exhaust system, loads, Inverter/Charger, choke, demand regulator, carburetor, generator drive system, generator windings, ignition, wire connections | Verify that Last Fault is FC 45: Yes, continue diagnosis; No, troubleshoot actual last fault; Inspect spark plug lead, kill lead terminal at magneto and measure magneto air gap: replace terminals, set gap or replace magnetos as necessary; Measure temperature of air intake and temperature rise across genset; remove blockage or prevent air recirculation; Dealers contact Distributor for technical support, Distributors contact factory for technical support |
| 47 | Ignition fault | Wire connections, windings, ignition system, generator drive system | Verify that Last Fault is FC 47: Yes, continue diagnosis; No, troubleshoot actual last fault; Alternating FC 47 and FC 37: Magneto gap too wide: reset magneto gap, retest; Test Magnetos: Disconnect Connector P1. Connect positive(+) meter lead to chassis ground. HGJAA, D, E, F – Measure continuity to negative lead at pin P1–4 and P1–5: replace magnetos as necessary. HGJAB, C – Measure continuity to negative lead at pin P1–15 and P1–20: replace magnetos as necessary; HGJAD only – Run genset in Engine Run Only and externally excite field with 12 VDC or 24 VDC and measure main and quadrature winding AC output; Non EFI only – If the genset will not stay running measure genset frequency, quadrature winding and main winding voltages using Break-Out Tool 420–0603 and Instruction Sheet R1098; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response: repair damaged generator drive system as necessary; Measure field, quadrature and main winding resistance: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to ground: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to each other: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Check brush alignment per PSB-682a; Verify that spark plug cables are secure on spark plugs: reconnect or replace as necessary; Inspect ignition kill leads in harness and at connector P1: repair or replace lead, terminal or pins as necessary; Measure spark plug gap: set gap or replace spark plugs as necessary; Verify ignition spark condition; Inspect spark plug lead, kill lead terminal at magneto and measure magneto air gap: replace terminals, set gap or replace magnetos as necessary; Dealers contact Distributor for technical support, Distributors contact factory for technical support |
| 48 | Field Sense Fault — Controller unable to sense field voltage | Faulty control | Verify that Last Fault is FC 48: Yes, continue diagnosis; No, troubleshoot actual last fault; Replace control. |
| 51 | Processor Failure — Processor error | Faulty control | Verify that Last Fault is FC 51: Yes, continue diagnosis; No, troubleshoot actual last fault; Replace control. |
| 52 | Fuel Injector Fault — Open or shorted fuel injector | P1–17, wire connections, fuel injector | Verify that Last Fault is FC 52: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure P1–17 open to ground on EFI set: ground lead as required for carburetor configuration; Inspect connector at injectors for looseness and damage, repair or replace connector as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Measure for continuity between P1–23 – INJ1 and P1–35 – INJ2: repair or replace harness as necessary; Measure for continuity to ground from P1–23, P1–35, INJ1 and INJ2: repair or replace harness as necessary; Replace injector; Dealers contact Distributor for technical support, Distributors contact factory for technical support. |
| 54 | MAT Sensor Fault — MAT sender input greater than 300K ohms | P1–17, wire connections, MAT sender | Verify that Last Fault is FC 54: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure P1–17 open to ground on EFI set: ground lead as required for carburetor configuration; Inspect connector at sender for looseness and damage, repair or replace connector as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Measure for continuity across harness between P1–25 – MAT(A) and P1–20 – MAT(B): repair or replace harness as necessary; Measure resistance of MAT: Replace sender as necessary; Dealers contact Distributor for technical support, Distributors contact factory for technical support. |
| 56 | MAP Sensor Fault — MAP sensor input less than 50kPa at start | P1–17, ambient pressure/altitude, wire connections, MAP sender, wide open throttle (WOT) during start | Verify that Last Fault is FC 56: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure P1–17 open to ground on EFI set: ground lead as required for carburetor configuration; Verify ambient pressure greater than 50kPa: change altitude; Inspect connector at sender for looseness and damage: repair or replace connector as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector |
| 12 | Overvoltage | ||
| 15 | Underfrequency | ||
| 27 | Voltage Sense Lost | ||
| 32 | Low Cranking Speed Sense | ||
| 37 | Invalid Set Configuration | ||
| 38 | Field Overload (Overvoltage) | ||
| 41 | Generator Rotor Fault | ||
| 57 | Overprime Fault | ||
| 2 | Low oil pressure shutdown — First-level shutdown code—Low oil pressure cutoff switch did not open | Low oil pressure cutoff switch did not open | Check engine oil level and add oil as necessary (Page 17); Drain excess oil (above dipstick Full mark.) |
| 3 | Service check shutdown — First-level shutdown code—Indicates fault with second-level shutdown code | Indicates fault with second-level shutdown code | Check the second-level shutdown code by pressing STOP once. The second-level shutdown code will have two-digits. The faults are listed in numerical order in this table. |
| 4 | Overcrank shutdown — First-level shutdown code—Cranking exceeded 30 seconds without engine starting | Cranking exceeded 30 seconds without engine starting | Gasoline Models – Check and fill the fuel tank, as necessary. (Note: The genset fuel pickup tube is probably higher up in the fuel tank than the vehicle engine pickup.); Prime the engine fuel system by holding the control switch at Stop/Prime for 30 seconds; Low Pressure LPG Models – Check and fill the LPG container, as necessary. On cold days the LPG container may have to be kept at least half full to provide the rate of vaporization necessary to keep up with the genset fuel demand; Open any closed fuel valves; Secure the spark plug leads on the spark plugs (Page 20); Replace the spark plugs (Page 20); Service the air cleaner (Page 19). |
| 12 | Overvoltage shutdown — Controller unable to maintain rated voltage | Controller unable to maintain rated voltage | See an authorized Onan dealer. |
| 13 | Undervoltage shutdown — Controller unable to maintain rated voltage | Controller unable to maintain rated voltage | Reduce the number of connected appliances, especially when air conditioners and battery chargers are running. |
| 14 | Overfrequency shutdown — Engine governor unable to maintain rated frequency | Engine governor unable to maintain rated frequency | See an authorized Onan dealer. |
| 15 | Underfrequency shutdown — Engine governor unable to maintain rated frequency | Engine governor unable to maintain rated frequency | Reduce the number of connected appliances, especially when air conditioners and battery chargers are running. |
| 19 | Governor actuator shutdown — Controller sensed open or shorted circuit | Controller sensed open or shorted circuit | See an authorized Onan dealer. |
| 22 | Governor actuator overload shutdown — Duration of operation at or near full-duty cycle beyond design limit | Duration of operation at or near full-duty cycle beyond design limit | Reduce the number of connected appliances, especially when air conditioners and battery chargers are running; Service the air cleaner (Page 19); Check for and repair a blocked exhaust system. |
| 23 | Low oil pressure cutoff switch shutdown — Controller sensed switch still open during start—not a running fault | Controller sensed switch still open during start—not a running fault | See an authorized Onan dealer. |
| 27 | Voltage sense shutdown — Controller unable to sense output voltage | Controller unable to sense output voltage | See an authorized Onan dealer. |
| 29 | High battery voltage shutdown — Voltage across battery system greater than 19 volts | Voltage across battery system greater than 19 volts | Check battery bank connections and reconnect if necessary so that the 12 volt batteries serving the genset are connected in parallel (12 volt) rather than in series (24 volt); Select a lower battery boost charge rate. |
| 31 | Overspeed shutdown — Engine speed greater than 3400 rpm | Engine speed greater than 3400 rpm | See an authorized Onan dealer. |
| 32 | Low cranking speed shutdown — Cranking speed less than 180 rpm for more than 2 seconds | Cranking speed less than 180 rpm for more than 2 seconds | Clean and tighten the positive (+) and negative (–) battery cable connections at the battery and at the genset; Recharge or replace the battery. Refer to the battery manufacturer's recommendations; Replace engine oil with oil of proper viscosity for ambient temperatures (Page 6). (High oil viscosity can slow down cranking speed.) |
| 35 | Control card failure shutdown — Microprocessor EEPROM error during self-test | Microprocessor EEPROM error during self-test | See an authorized Onan dealer. |
| 36 | Engine stopped shutdown — Engine stopped without command by controller | Engine stopped without command by controller | Gasoline Models – Check and fill the fuel tank, as necessary. (Note: The genset fuel pickup tube is probably higher up in the fuel tank than the vehicle engine pickup.); Low Pressure LPG Models – Check and fill the LPG container, as necessary. On cold days the LPG container may have to be kept at least half full to provide the rate of vaporization necessary to keep up with the genset fuel demand; Secure the spark plug leads on the spark plugs (Page 20); Replace the spark plugs (Page 20); Service the air cleaner (Page 19); Check for mechanical damage. |
| 37 | Invalid genset configuration shutdown — Wrong frequency/rpm ratio | Wrong frequency/rpm ratio | See an authorized Onan dealer. |
| 38 | Overcurrent (field overload) shutdown — Low power factor loads | Low power factor loads | Reduce the number of appliances running at the same time, especially those with high motor starting loads such as air conditioners; Have air conditioners and other appliances checked for proper operation. (A locked compressor rotor can cause very low power factor.) |
| 41 | Generator rotor shutdown — Controller unable to sense field or output voltage | Controller unable to sense field or output voltage | See an authorized Onan dealer. |
| 42 | Processor shutdown — Microprocessor ROM error during self-test | Microprocessor ROM error during self-test | See an authorized Onan dealer. |
| 43 | Processor shutdown — Microprocessor RAM error during self-test | Microprocessor RAM error during self-test | See an authorized Onan dealer. |
| 45 | Speed sense shutdown — Controller unable to sense quadrature frequency | Controller unable to sense quadrature frequency | See an authorized Onan dealer. |
| 47 | Ignition shutdown — Controller unable to sense ignition | Controller unable to sense ignition | See an authorized Onan dealer. |
| 48 | Generator field sense shutdown — Controller unable to sense field voltage | Controller unable to sense field voltage | See an authorized Onan dealer. |
| 51 | Processor shutdown — Microprocessor malfunction | Microprocessor malfunction | See an authorized Onan dealer. |
| 52 | Fuel injector shutdown — Open or short circuit in fuel injector | Open or short circuit in fuel injector | See an authorized Onan dealer. |
| 54 | MAT sender shutdown — Open or short circuit in MAT sender | Open or short circuit in MAT sender | See an authorized Onan dealer. |
| 56 | MAP sender shutdown — Open or short circuit in MAP sender | Open or short circuit in MAP sender | See an authorized Onan dealer. |
| 57 | Overprime shutdown — Prime mode exceeded 3 minutes | Prime mode exceeded 3 minutes | Check for and remove any object that may be holding either control switch (remote or local) in the prime position. |
| CODE NO. 12 | OVERVOLTAGE SHUTDOWN—Controller unable to maintain rated voltage | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 13 | UNDERVOLTAGE SHUTDOWN—Controller unable to maintain rated voltage | Corrective Action: Reduce the number of connected appliances, especially when air conditioners and battery chargers are running. | |
| CODE NO. 14 | OVERFREQUENCY SHUTDOWN—Engine governor unable to maintain rated frequency | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 15 | UNDERFREQUENCY SHUTDOWN—Engine governor unable to maintain rated frequency | Corrective Action: Reduce the number of connected appliances, especially when air conditioners and battery chargers are running. | |
| CODE NO. 19 | GOVERNOR ACTUATOR SHUTDOWN—Controller sensed open or shorted circuit | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 22 | GOVERNOR ACTUATOR OVERLOAD SHUTDOWN—Duration of operation at or near full-duty cycle beyond design limit | 1. Reduce the number of connected appliances, especially when air conditioners and battery chargers are running. 2. Service the air cleaner (Page 19). 3. Check for and repair a blocked exhaust system. | |
| CODE NO. 23 | LOW OIL PRESSURE CUTOFF SWITCH SHUTDOWN—Controller sensed switch still open during start—not a running fault | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 27 | VOLTAGE SENSE SHUTDOWN—Controller unable to sense output voltage | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 29 | HIGH BATTERY VOLTAGE SHUTDOWN—Voltage across battery system greater than 19 volts | 1. Check battery bank connections and reconnect if necessary so that the 12 volt batteries serving the genset are connected in parallel (12 volt) rather than in series (24 volt). 2. Select a lower battery boost charge rate. | |
| CODE NO. 31 | OVERSPEED SHUTDOWN—Engine speed greater than 3400 rpm | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 32 | LOW CRANKING SPEED SHUTDOWN—Cranking speed less than 180 rpm for more than 2 seconds | 1. Clean and tighten the positive (+) and negative (–) battery cable connections at the battery and at the genset. 2. Recharge or replace the battery. Refer to the battery manufacturer’s recommendations. 3. Replace engine oil with oil of proper viscosity for ambient temperatures (Page 6). (High oil viscosity can slow down cranking speed.) | |
| CODE NO. 35 | CONTROL CARD FAILURE SHUTDOWN—Microprocessor EEPROM error during self-test | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 36 | ENGINE STOPPED SHUTDOWN—Engine stopped without command by controller | 1. Gasoline Models – Check and fill the fuel tank, as necessary. 2. Low Pressure LPG Models – Check and fill the LPG container, as necessary. On cold days the LPG container may have to be kept at least half full to provide the rate of vaporization necessary to keep up with the genset fuel demand. 3. Secure the spark plug leads on the spark plugs (Page 20). 4. Replace the spark plugs (Page 20). 5. Service the air cleaner (Page 19).= 6. Check for mechanical damage. | |
| CODE NO. 37 | INVALID GENSET CONFIGURATION SHUTDOWN—Wrong frequency/rpm ratio | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 38 | OVERCURRENT (FIELD OVERLOAD) SHUTDOWN—Low power factor loads | 1. Reduce the number of appliances running at the same time, especially those with high motor starting loads such as air conditioners. 2. Have air conditioners and other appliances checked for proper operation. (A locked compressor rotor can cause very low power factor.) | |
| CODE NO. 41 | GENERATOR ROTOR SHUTDOWN—Controller unable to sense field or output voltage | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 42 | PROCESSOR SHUTDOWN—Microprocessor ROM error during self-test | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 43 | PROCESSOR SHUTDOWN—Microprocessor RAM error during self-test | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 45 | SPEED SENSE SHUTDOWN—Controller unable to sense quadrature frequency | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 47 | IGNITION SHUTDOWN—Controller unable to sense ignition | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 48 | GENERATOR FIELD SENSE SHUTDOWN—Controller unable to sense field voltage | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 51 | PROCESSOR SHUTDOWN—Microprocessor malfunction | Corrective Action: See an authorized Onan dealer. | |
| CODE NO. 52 | FUEL INJECTOR SHUTDOWN—Open or short circuit in fuel injector | Corrective Action: See an authorized Onan dealer. | |
| 2 | Low Oil Pressure Fault | Low/high oil level; faulty switch; faulty oil pressure relief valve; fault oil pump | Verify that Last Fault is FC 2: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure oil level: add or drain oil as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB-676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Measure continuity change across start/stop switch between rest and under simulated pressure: replace switch as necessary; HGJAB, C — Measure continuity between ground and P1-13: repair or replace harness as necessary. HGJAA, D, E, F — Measure continuity between ground and P1-6: repair or replace harness as necessary; Measure oil pressure with mechanical gauge: repair or replace relief valve and oil pump as necessary |
| 3 | Service Check Fault — Single-Digit Fault to indicate shutdown due to a Two-Digit Fault | Any Two-Digit Fault Code | Verify that Last Fault is FC 3: Yes, continue diagnosis; No, troubleshoot actual last fault; While LED is flashing three times press stop once (1 second duration): trouble shoot Two-Digit Fault Code |
| 4 | Overcrank — Controller unable to sense genset frequency after 30 seconds of holding start switch | Faulty switch; faulty external start command; fuel supply; air fuel mixture; exhaust system; wire connections; starter; ignition system | |
| 12 | Overvoltage — Instantaneous Fault − AC voltage S1−S2 greater than 150 VAC; Delayed Fault − AC voltage S1−S2 greater than 138 VAC, but less than 150 VAC for 3 continuous minutes | Genset loads; Inverter/Charger; wire connections; AC sense transformer; windings | Verify that Last Fault is FC 12: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure AC voltage; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response: repair damaged generator drive system as necessary; Cycle loads to determine if a particular load causes fault: diagnose faulty load as necessary; Determine Inverter/Charger battery charge rate (typical default is 80 percent): if adjustable reduce to 30 percent; Verify balanced loads in 120/240 VAC applications: balance loads within 10 percent line−to−line as required; HGJAD only − Run genset in Engine Run Only mode and externally excite field F1−F2 with 12 VDC or 24 VDC and measure main and quadrature winding AC output; Non EFI − If the genset will not stay running measure genset frequency, quadrature winding and main winding voltages using Break-Out Tool 420−0603 and Instruction Sheet R1098; Remove connector P1 from control and re-install and try to start genset: inspect, repair or replace P1 connector pins as necessary; Measure field, quadrature and main winding resistance: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to ground: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to each other: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Check brush alignment per PSB-682a; Dealers contact Distributor for technical support, Distributors contact factory for technical support |
| 13 | Undervoltage — AC voltage S1−S2 less than 108 VAC for 5 continuous seconds | Genset loads; Inverter/Charger; wire connections; generator drive system; windings; AC sense transformer; windings | Verify that Last Fault is FC 13: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure AC voltage; Measure AC voltage in and out of sense transformer (if so equipped): repair wire connection, replace sense transformer as necessary; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response: repair damaged generator drive system as necessary; Cycle loads to determine if a particular load will cause fault: diagnose faulty load as necessary; Determine battery charge rate (typical default is 80 percent): if adjustable reduce to 30 percent; Verify balanced loads in 120/240 VAC applications: balance loads within 10 percent line−to−line as required; HGJAD only − Run genset in Engine Run Only mode and externally excite field F1−F2 with 12 VDC or 24 VDC and measure main and quadrature winding AC output; Non EFI − If the genset will not stay running measure genset frequency |
| 17 | Fuel Pump Fault — Only Active Prior to 2001 − Open fuel pump circuit at control | Wire connections; harness leads; faulty fuel pump | Verify that Last Fault is FC 17: Yes, continue diagnosis; No, troubleshoot actual last fault; Verify fuel pump operation in prime mode, if pump operates fault condition has been cleared verify harness connections, no further troubleshooting; HGJAA, D Check continuity across fuse F1; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB−676: insert, repair or replace pins as necessary; Reconnect P1 connector, prime genset to verify pump operation and test run genset for fault occurrence; Measure continuity between E2 fuel pump leads; replace terminals or fuel pump as necessary; Measure voltage between fuel pump E2 + and ground while priming; replace terminals, harness leads or control as necessary |
| 19 | Governor Actuator (EFI Only) — Shorted or open connection between governor leads after pressing start | Wire connections; P1−17; governor actuator (Does Not Pertain to Model HGJAA) | Verify that Last Fault is FC 19: Yes, continue diagnosis; No, troubleshoot actual last fault; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB−676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; P1−17 open to ground on EFI Models: ground lead as required for carburetor configuration; Verify actuator function by applying DC voltage to terminals: replace actuator as necessary; Measure resistance between actuator terminals; repair or replace connections as necessary, replace governor actuator; Measure continuity between P1−28 and actuator lead; repair or replace terminals and leads as necessary; Measure DC voltage at actuator while starting: replace controller as necessary |
| 22 | Governor Actuator Overload (EFI Only) — Only active Prior to 2001 − Maximum governor output (PWM) for 10 continuous seconds | Genset loads; Inverter/Charger; wire connections; fuel supply; air fuel mixture; exhaust system; governor actuator; ignition system | Verify that Last Fault is FC 22: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure AC current while running genset with vehicle loads: identify faulty or short cycling loads or reduce vehicle loads as necessary; Determine battery charge rate (typical default is 80 percent): if adjustable reduce to 30 percent; Measure genset load capability with shop load bank (derate for altitude and temperature as necessary); Measure AC frequency and droop while running; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response: repair damaged generator drive system as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB−676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Check air filter cleanliness; replace air filter as necessary; Check intake manifold and gaskets for air leaks: tighten fasteners and replace gaskets and manifold as necessary; Check for blocked or damaged exhaust system: repair or replace exhaust components as necessary; Measure fuel pump pressure/flow: replace fuel filter, pressure regulator or fuel pump as necessary; Verify actuator function by applying DC voltage to terminals: replace actuator as necessary; Check throttle body for binding; inspect spring for dirt and debris: clean spring, replace throttle body as necessary; Verify that spark plug cables are secure on spark plugs: reconnect or replace as necessary; Inspect ignition kill leads in harness and at connector P1: repair or replace lead, terminal or pins as necessary; Test Magnetos: Disconnect Connector P1; Connect positive(+) meter lead to chassis ground; HGJAA, D, E, F − Measure continuity to negative lead at pin P1−4 and P1−5: replace magnetos as necessary; HGJAB, C − Measure continuity to negative lead at pin P1−15 and P1−20: replace magnetos as necessary; Measure spark plug gap: set gap or replace spark plugs as necessary; Verify ignition spark condition; Inspect spark plug cables, kill lead terminal at magneto and measure magneto air gap: replace terminals, set gap or replace magnetos as necessary; Dealers contact Distributor for technical support, Distributors contact factory for technical support |
| 23 | Oil Pressure Switch Fault — Only Active Prior to 2001 − Continuous open on oil pressure switch input before cranking | Wire connections; faulty switch | Verify that Last Fault is FC 23: Yes, continue diagnosis; No, troubleshoot actual last fault; Verify harness lead is connected to switch: repair or replace terminal as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence; Measure continuity to ground at switch and through harness at P1 connector: replace switch, repair or replace harness as necessary |
| 27 | Voltage Sense Lost — No Sense Voltage (0 VAC across S1−S2) for 1 continuous second after start disconnect | Genset loads; Inverter/Charger; VAC sense transformer; engine governor function; fuel supply; choke; demand regulator; carburetor; generator windings; ignition; wire connections; temperature | Verify that Last Fault is FC 27: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure AC voltage; Determine battery charge rate (typical default is 80 percent): if adjustable reduce to 30 percent; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB−676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Check air filter cleanliness; replace air filter as necessary; Check for blocked or damaged exhaust system: repair or replace exhaust components as necessary; HGJAD only − Run genset in Engine Run Only and externally excite field with 12 VDC or 24 VDC and measure main and quadrature winding AC output; Non EFI only |
| 33 | Fault Code 33 — Single-Digit Fault to indicate shutdown due to Two-Digit Fault Code | Fault Code 3 interpreted as a non-assigned Fault Code 33 | Verify that Last Fault is FC 3 Yes, continue diagnosis; No, troubleshoot actual last fault; While LED is flashing three times press stop once (1 second duration): trouble shoot Two-Digit Fault Code |
| 35 | Control Card Failure — EEPROM (programming variables) error during self test | Faulty program | Verify that Last Fault is FC 35: Yes, continue diagnosis; No, troubleshoot actual last fault; Replace control |
| 36 | Genset Stopped Without Fault Condition — RPM less than 500 and Sense Voltage S1−S2 at 0 VAC when no other fault condition occurred | Auto Gen Start (AGS); fuel supply; air fuel mixture; exhaust system; loads; Inverter/Charger; choke; demand regulator; carburetor; generator drive system; generator windings; ignition; wire connections | Verify that Last Fault is FC 36: Yes, continue diagnosis; No, troubleshoot actual last fault; Verify whether AGS stopped genset: Yes, disable AGS or explain AGS function to customer (see PSB-666); No, continue diagnosis; Verify engine rotation manually: repair engine damage as necessary; Disconnect genset control P1 connector |
| 37 | Configuration Fault — Configuration is determined by ratio of quadrature frequency / ignition speed | Wire connections; windings; ignition system; drive belt slippage; generator drive system | Verify that Last Fault is FC 37: Yes, continue diagnosis; No, troubleshoot actual last fault; Alternating FC 37 and FC 47: Magneto gap to wide: reset magneto gap, retest; HGJAD only − Run genset in Engine Run Only and externally excite field with 12 VDC or 24 VDC and measure main and quadrature winding AC output; Non EFI only − If the genset will not stay running measure genset frequency, quadrature winding and main winding voltages using Break-Out Tool 420−0603 and Instruction Sheet R1098; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response: repair damaged generator drive system as necessary; Measure field, quadrature and main winding resistance: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to ground: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to each other: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Check brush alignment per PSB-682a; Verify that spark plug cables are secure on spark plugs: reconnect or replace as necessary; Inspect ignition kill leads in harness and at connector P1: repair or replace lead, terminal or pins as necessary; Test Magnetos: Disconnect Connector P1; Connect positive(+) meter lead to chassis ground; HGJAA, D, E, F − Measure continuity to negative lead at pin P1−4 and P1−5: replace magnetos as necessary; HGJAB, C − Measure continuity to negative lead at pin P1−15 and P1−20: replace magnetos as necessary; Measure spark plug gap: set gap or replace spark plugs as necessary; Verify ignition spark condition; Inspect spark plug lead, kill lead terminal at magneto and measure magneto air gap: replace terminals, set gap or replace magnetos as necessary; Dealers contact Distributor for technical support, Distributors contact factory for technical support |
| 38 | Field Overload (Overvoltage) — Field voltage (F1−F1) greater than 150 VDC for 10 continuous seconds | Loads; Inverter/Charger; windings; fuel supply; governor system | Verify that Last Fault is FC 38: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure F1−F2 DC voltage; Measure AC current while running genset with vehicle loads: identify faulty or short cycling loads; Determine battery charge rate (typical default is 80 percent): if adjustable reduce to 30 percent; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB−676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Measure genset load capability with shop load bank (derate for altitude and temperature as necessary); Measure genset frequency and droop while running; Check governor, actuator, linkage and spring for debris, damage and looseness: readjust and repair as necessary; Check air filter cleanliness; replace air filter as necessary; Check for blocked or damaged exhaust system: repair or replace exhaust components as necessary; All Gasoline Models |
| 42 | Processor Fault — ROM (programming variables) error during self test | Faulty program | Verify that Last Fault is FC 42: Yes, continue diagnosis; No, troubleshoot actual last fault; Replace control |
| 43 | Processor Fault — RAM (programming variables) error during self test | Faulty program | Verify that Last Fault is FC 43: Yes, continue diagnosis; No, troubleshoot actual last fault; Replace control |
| 45 | Speed Sense Fault — While running quadrature frequency dropped to 0Hz for 1 continuous second | Auto Gen Start (AGS); fuel supply; air fuel mixture; exhaust system; loads; Inverter/Charger; choke; demand regulator; carburetor; generator drive system; generator windings; ignition; wire connections | Verify that Last Fault is FC 45: Yes, continue diagnosis; No, troubleshoot actual last fault; Verify whether AGS stopped genset: Yes, disable AGS or explain AGS function to customer (see PSB-666); No, continue diagnosis; Verify engine rotation manually: repair engine damage as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB−676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Check air filter cleanliness; replace air filter as necessary; Check for blocked or damaged exhaust system: repair or replace exhaust components as necessary; Measure AC current while running genset with vehicle loads: identify faulty or short cycling loads; Determine battery charge rate (typical default is 80 percent): if adjustable reduce to 30 percent; Measure genset load capability with shop load bank (derate for altitude and temperature as necessary); HGJAD only − Run genset in Engine Run Only and externally excite field F1−F2 with 12 VDC or 24 VDC and measure main and quadrature winding AC output; Non EFI − Verify genset operation and outputs with Break-Out Tool 420−0603 and Instruction Sheet R1098; Measure genset frequency and droop while running; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response: repair damaged generator drive system as necessary; All Gasoline Models; All Gasoline Carburetor Models; All Gasoline EFI Models; Propane Models; Check governor, actuator, linkage and spring for debris, damage and looseness: readjust and repair as necessary; Verify that spark plug cables are secure on spark plugs: reconnect or replace as necessary; Test Magnetos: Disconnect Connector P1; Connect positive(+) meter lead to chassis ground; HGJAA, D, E, F − Measure continuity to negative lead at pin P1−4 and P1−5: replace magnetos as necessary; HGJAB, C − Measure continuity to negative lead at pin P1−15 and P1−20: replace magnetos as necessary; Inspect ignition kill leads in harness and at connector P1: repair or replace lead, terminal or pins as necessary; Measure spark plug gap: set gap or replace spark plugs as necessary; Verify ignition spark condition; Inspect spark plug lead, kill lead terminal at magneto and measure magneto air gap: replace terminals, set gap or replace magnetos as necessary; Measure temperature of air intake and temperature rise across genset; remove blockage or prevent air recirculation; Dealers contact Distributor for technical support, Distributors contact factory for technical support |
| 47 | Ignition Fault — HGJAB, C − No ignition signal at P1−15 for 1 continuous second; HGJAA − No ignition signal at P1−5 for 1 continuous second; HGJAD, E, F prior to 2004 − No ignition signal at P1−5 for 1 continuous second; HGJAD, E, F after 2004 in Engine Run Only mode only − No ignition signal at P1−5 for continuous second | Wire connections; windings; ignition system; generator drive system | Verify that Last Fault is FC 47: Yes, continue diagnosis; No, troubleshoot actual last fault; Alternating FC 47 and FC 37: Magneto gap too wide: reset magneto gap, retest; Test Magnetos: Disconnect Connector P1; Connect positive(+) meter lead to chassis ground; HGJAA, D, E, F − Measure continuity to negative lead at pin P1−4 and P1−5: replace magnetos as necessary; HGJAB, C − Measure continuity to negative lead at pin P1−15 and P1−20: replace magnetos as necessary; HGJAD only − Run genset in Engine Run Only and externally excite field with 12 VDC or 24 VDC and measure main and quadrature winding AC output; Non EFI only − If the genset will not stay running measure genset frequency, quadrature winding and main winding voltages using Break-Out Tool 420−0603 and Instruction Sheet R1098; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response: repair damaged generator drive system as necessary; Measure field, quadrature and main winding resistance: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to ground: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to each other: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Check brush alignment per PSB-682a; Verify that spark plug cables are secure on spark plugs: reconnect or replace as necessary; Inspect ignition kill leads in harness and at connector P1: repair or replace lead, terminal or pins as necessary; Measure spark plug gap: set gap or replace spark plugs as necessary; Verify ignition spark condition; Inspect spark plug lead, kill lead terminal at magneto and measure magneto air gap: replace terminals, set gap or replace magnetos as necessary; Dealers contact Distributor for technical support, Distributors contact factory for technical support |
| 52 | Fuel Injector Fault — Open or shorted fuel injector | P1−17; wire connections; fuel injector (Does not pertain to HGJAA Models) | Verify that Last Fault is FC 52: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure P1−17 open to ground on EFI set: ground lead as required for carburetor configuration; Inspect connector at injectors for looseness and damage, repair or replace connector as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB−676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Measure for continuity between P1−23 − INJ1 and P1−35 − INJ2: repair or replace harness as necessary; Measure for continuity to ground from P1−23, P1−35, INJ1 and INJ2: repair or replace harness as necessary; Replace injector; Dealers contact Distributor for technical support, Distributors contact factory for technical support |
| 54 | MAT SENSOR FAULT | MAT sender input greater than 300K ohms; P1−17; wire connections; MAT sender | Verify that Last Fault is FC 54: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure P1−17 open to ground on EFI set: ground lead as required for carburetor configuration; Inspect connector at sender for looseness and damage, repair or replace connector as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB−676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Measure for continuity across harness between P1−25 − MAT(A) and P1−20 − MAT(B): repair or replace harness as necessary; Measure resistance of MAT: Replace sender as necessary; Dealers contact Distributor for technical support, Distributors contact factory for technical support |
| 56 | MAP SENSOR FAULT | MAP sensor input less than 50kPa at start; P1−17; ambient pressure/altitude; wire connections; MAP sender; wide open throttle (WOT) during start | Verify that Last Fault is FC 56: Yes, continue diagnosis; No, troubleshoot actual last fault |
| 14 | Overfrequency | ||
| 29 | High Battery Voltage | ||
| 31 | Overspeed Fault (HGJAD, E, F Models Only) | ||
| No. 4 | The genset does not start after two or three tries. | Wait 5 seconds for the control to reset before trying again. | |
| 1 | High engine coolant temperatures | ||
| 2 | LOW OIL PRESSURE SHUTDOWN | Low oil pressure cutoff switch did not open | Check engine oil level and add oil as necessary (Page Section 4.2); Drain excess oil (above dipstick Full mark.) |
| 3 | SERVICE CHECK SHUTDOWN | Indicates fault with second-level shutdown code | Check the second-level shutdown code by pressing STOP once. The second-level shutdown code will have two-digits. The faults are listed in numerical order in this table. |
| 4 | OVERCRANK SHUTDOWN | Cranking exceeded 30 seconds without engine starting | Gasoline Models -Check and fill the fuel tank, as necessary. (Note: The genset fuel pickup tube is probably higher up in the fuel tank than the vehicle engine pickup.); Prime the engine fuel system by holding the control switch at Stop/Prime for 30 seconds; Low Pressure LPG Models - Check and fill the LPG container, as necessary. On cold days the LPG container may have to be kept at least half full to provide the rate of vaporization necessary to keep up with the genset fuel demand; Open any closed fuel valves; Secure the spark plug leads on the spark plugs (Page Section 4.6); Replace the spark plugs (Page Section 4.6); Service the air cleaner (Page Section 4.5). |
| 12 | OVERVOLTAGE SHUTDOWN | Controller unable to maintain rated voltage | See an authorized Onan dealer. |
| 13 | UNDERVOLTAGE SHUTDOWN | Controller unable to maintain rated voltage | Reduce the number of connected appliances, especially when air conditioners and battery chargers are running. |
| 14 | OVERFREQUENCY SHUTDOWN | Engine governor unable to maintain rated frequency | See an authorized Onan dealer. |
| 15 | UNDERFREQUENCY SHUTDOWN | Engine governor unable to maintain rated frequency | Reduce the number of connected appliances, especially when air conditioners and battery chargers are running. |
| 19 | GOVERNOR ACTUATOR SHUTDOWN | Controller sensed open or shorted circuit | See an authorized Onan dealer. |
| 22 | GOVERNOR ACTUATOR OVERLOAD SHUTDOWN | Duration of operation at or near full-duty cycle beyond design limit | Reduce the number of connected appliances, especially when air conditioners and battery chargers are running; Service the air cleaner (Page Section 4.5); Check for and repair a blocked exhaust system. |
| 23 | LOW OIL PRESSURE CUTOFF SWITCH SHUTDOWN | Controller sensed switch still open during start—not a running fault | See an authorized Onan dealer. |
| 27 | VOLTAGE SENSE SHUTDOWN | Controller unable to sense output voltage | See an authorized Onan dealer. |
| 29 | HIGH BATTERY VOLTAGE SHUTDOWN | Voltage across battery system greater than 19 volts | Check battery bank connections and reconnect if necessary so that the 12 volt batteries serving the genset are connected in parallel (12 volt) rather than in series (24 volt); Select a lower battery boost charge rate. |
| 31 | OVERSPEED SHUTDOWN | Engine speed greater than 3400 rpm | See an authorized Onan dealer. |
| 32 | LOW CRANKING SPEED SHUTDOWN | Cranking speed less than 180 rpm for more than 2 seconds | Clean and tighten the positive (+) and negative (-) battery cable connections at the battery and at the genset; Recharge or replace the battery. Refer to the battery manufacturer's recommendations; Replace engine oil with oil of proper viscosity for ambient temperatures (Page Section 2.5). (High oil viscosity can slow down cranking speed.) |
| 35 | CONTROL CARD FAILURE SHUTDOWN | Microprocessor EEPROM error during self-test | See an authorized Onan dealer. |
| 36 | ENGINE STOPPED SHUTDOWN | Engine stopped without command by controller | Gasoline Models -Check and fill the fuel tank, as necessary. (Note: The genset fuel pickup tube is probably higher up in the fuel tank than the vehicle engine pickup.); Low Pressure LPG Models - Check and fill the LPG container, as necessary. On cold days the LPG container may have to be kept at least half full to provide the rate of vaporization necessary to keep up with the genset fuel demand; Secure the spark plug leads on the spark plugs (Page Section 4.6); Replace the spark plugs (Page Section 4.6); Service the air cleaner (Page Section 4.5); Check for mechanical damage. |
| 37 | INVALID GENSET CONFIGURATION SHUTDOWN | Wrong frequency/rpm ratio | See an authorized Onan dealer. |
| 38 | OVERCURRENT (FIELD OVERLOAD) SHUTDOWN | Low power factor loads | Reduce the number of appliances running at the same time, especially those with high motor starting loads such as air conditioners; Have air conditioners and other appliances checked for proper operation. (A locked compressor rotor can cause very low power factor.) |
| 41 | GENERATOR ROTOR SHUTDOWN | Controller unable to sense field or output voltage | See an authorized Onan dealer. |
| 42 | PROCESSOR SHUTDOWN | Microprocessor ROM error during self-test | See an authorized Onan dealer. |
| 43 | PROCESSOR SHUTDOWN | Microprocessor RAM error during self-test | See an authorized Onan dealer. |
| 45 | SPEED SENSE SHUTDOWN | Controller unable to sense quadrature frequency | See an authorized Onan dealer. |
| 47 | IGNITION SHUTDOWN | Controller unable to sense ignition | See an authorized Onan dealer. |
| 48 | GENERATOR FIELD SENSE SHUTDOWN | Controller unable to sense field voltage | See an authorized Onan dealer. |
| 51 | PROCESSOR SHUTDOWN | Microprocessor malfunction | See an authorized Onan dealer. |
| 52 | FUEL INJECTOR SHUTDOWN | Open or short circuit in fuel injector | See an authorized Onan dealer. |
| 54 | MAT SENDER SHUTDOWN | Open or short circuit in MAT sender | See an authorized Onan dealer. |
| 56 | MAP SENDER SHUTDOWN | Open or short circuit in MAP sender | See an authorized Onan dealer. |
| 57 | OVERPRIME SHUTDOWN | Prime mode exceeded 3 minutes | Check for and remove any object that may be holding either control switch (remote or local) in the prime position. |
| 58 | Exhaust Gas Temp Shutdown/Fault | Exhaust gas temperatures reach 650C (1202F) for 2 secs when the set is running | See an authorized Onan dealer |
| 81 | OVERPRIME SHUTDOWN | While running, EGT temp falls below 60C (140F) for 2 minutes - OR - if EGT temperature is not above 60C (140F) after 2 minutes from starting, set will shut down | See an authorized Onan dealer |
| 82 | Exhaust Gas Temp Shutdown/Fault | With the set running and/or startup - control reads 1000C (1832F) for 1 second | See an authorized Onan dealer |
| CODE NO. 52 | FUEL INJECTOR SHUTDOWN | (Open or short circuit in fuel injector) | See an authorized Onan dealer. |
| CODE NO. 54 | MAT SENDER SHUTDOWN | (Open or short circuit in MAT sender) | See an authorized Onan dealer. |
| CODE NO. 56 | MAP SENDER SHUTDOWN | (Open or short circuit in MAP sender) | See an authorized Onan dealer. |
| CODE NO. 57 | OVERPRIME SHUTDOWN | (Prime mode exceeded 3 minutes) | Check for and remove any object that may be holding either control switch (remote or local) in the prime position. |
| CODE NO. 58 | Exhaust Gas Temp Shutdown/Fault | (Exhaust gas temperatures reach 650C (1202F) for 2 secs when the set is running) | See an authorized Onan dealer |
| 2 | Low Oil Pressure — Indicates that the low oil pressure cutoff switch did not open. | Check engine oil level: if the dipstick indicates oil is low, add oil; if oil is above the full mark on dipstick, drain excess oil. | |
| 3 | Service Check | See second-level fault code. | |
| 4 | Over Crank — Indicates that cranking exceeded 30 seconds without engine starting. | Low fuel level; low LPG level; loose spark plug lead(s) or faulty spark plug(s); dirty air filter element; oil viscosity too high for ambient temperature; fuel or air leak at fuel fittings; clogged fuel filter. | Check fuel level and fill the fuel tank if low; prime the engine fuel system by positioning the control switch to STOP/PRIME for 30 seconds; check and fill the LPG container as necessary; secure the spark plug lead(s) on the spark plug(s); replace the spark plug(s); replace the air filter if dirty; replace engine oil with oil of proper viscosity for the ambient temperature; tighten any fuel fitting if there is a fuel or air leak and reprime the engine fuel system by positioning the control switch to STOP/PRIME for 30 seconds; replace fuel filter. |
| 12 | Over Voltage — Indicates the control is unable to maintain rated voltage. | Contact local dealer or distributor. | |
| 13 | Under Voltage — Indicates the control is unable to maintain rated voltage. | Reduce load: reduce the number of connected appliances, especially air conditioners and battery chargers (review load management in Loading the Generator Set). | |
| 14 | Over Frequency — Indicates the engine governor is unable to maintain rated frequency. | Contact local dealer or distributor. | |
| 15 | Under Frequency — Indicates the engine governor is unable to maintain rated frequency. | Reduce load: reduce the number of connected appliances, especially air conditioners and battery chargers (review load management in Loading the Generator Set). | |
| 19 | Governor Actuator — Indicates the control sensed an open or shorted circuit. | Contact local dealer or distributor. | |
| 22 | Governor Actuator Overload — Indicates the duration of operation is near full-duty cycle beyond design limit. | Excessive load; dirty air filter element; blocked exhaust system. | Reduce load: reduce the number of connected appliances, especially air conditioners and battery chargers (review load management in Loading the Generator Set); replace the air filter if dirty; if exhaust system is blocked, remove blockage. |
| 23 | Low Oil Pressure Cutoff Switch — Indicates the control sensed that switch is still open during start (not a running start). | Contact local dealer or distributor. | |
| 27 | Voltage Sense — Indicates the control is unable to sense output voltage. | Contact local dealer or distributor. | |
| 29 | High Battery Voltage — Indicates that voltage across the battery system is greater than 19 Volts. | Check battery bank connections and reconnect if necessary so that the 12 Volt batteries serving the generator set are connected in parallel (12 Volt) rather than in series (24 Volt); select a lower battery boost charge rate. | |
| 31 | Over Speed — Indicates that engine speed is greater than 3400 RPM. | Contact local dealer or distributor. | |
| 32 | Low Cranking Speed — Indicates that cranking speed is less than 180 RPM for more than 2 seconds. | Loose or dirty battery cable connections; discharged or faulty battery; oil viscosity too high for ambient temperature. | Clean and tighten the positive (+) and negative (–) battery cable connections at the battery and at the generator set; recharge or replace the battery (refer to the battery manufacturer's recommendations); replace engine oil with oil of proper viscosity for the ambient temperature. |
| 35 | Control Card Failure — Indicates that a microprocessor EEPROM error occurred during self test. | Contact local dealer or distributor. | |
| 36 | Engine Stopped — Indicates that the engine stopped without receiving a command from the control. | Low fuel level; low LPG level; loose spark plug lead(s) or faulty spark plug(s); dirty air filter element; mechanical damage. | Check fuel level and fill the fuel tank if low; prime the engine fuel system by positioning the control switch to STOP/PRIME for 30 seconds; check and fill the LPG container as necessary; secure the spark plug lead(s) on the spark plug(s); replace the spark plug(s); replace the air filter if dirty; check for mechanical damage. |
| 37 | Invalid Generator Set Configuration — Indicates that the frequency/RPM ratio is wrong. | Contact local dealer or distributor. | |
| 38 | Over Current (Field Overload) — Indicates low power factor loads. | Low power factor loads; appliances not operating properly. | Reduce load: reduce the number of connected appliances, especially air conditioners and battery chargers (review load management in Loading the Generator Set); have air conditioners and other appliances checked for proper operation. |
| 41 | Generator Rotor — Indicates control is unable to sense field or output voltage. | Contact local dealer or distributor. | |
| 42 | Processor — Indicates that a microprocessor ROM error occurred during self test. | Contact local dealer or distributor. | |
| 43 | Processor — Indicates that a microprocessor RAM error occurred during self test. | Contact local dealer or distributor. | |
| 45 | Speed Sense — Indicates the control is unable to sense quadrature frequency. | Contact local dealer or distributor. | |
| 47 | Ignition — Indicates the control is unable to sense ignition. | Contact local dealer or distributor. | |
| 48 | Generator Field Sense — Indicates the control is unable to sense field voltage. | Contact local dealer or distributor. | |
| 51 | Processor — Indicates that a microprocessor malfunction has occurred. | Contact local dealer or distributor. | |
| 52 | Fuel Injector — Indicates that there is an open or short circuit in the fuel injector. | Contact local dealer or distributor. | |
| 54 | MAT Sender — Indicates that there is an open or short circuit in the MAT sender. | Contact local dealer or distributor. | |
| 56 | MAP Sender — Indicates that there is an open or short circuit in the MAP sender. | Contact local dealer or distributor. | |
| 57 | Over Prime — Indicates that priming exceeded 3 minutes. | An object may be holding either control switch (remote or generator set) in the STOP/PRIME position. | Check for and remove any object that may be holding either control switch (remote or generator set) in the STOP/PRIME position. |
| 58 | Exhaust Gas Temperature Shutdown — Indicates that the exhaust gas temperature reached 650°C (1202°F) for 2 seconds when the generator set was running. | Contact local dealer or distributor. | |
| 81 | Exhaust Gas Temperature Sensor Open — Indicates that the EGT temperature fell below 60°C (140°F) for 2 minutes when the generator set was running or the EGT temperature is not above 60°C (140°F) within 2 minutes of starting. | Contact local dealer or distributor. | |
| 82 | Exhaust Gas Temperature Sensor Shorted — Indicates that the control reads 1000°C (1832°F) for 1 second when the generator set was running or during startup. | Contact local dealer or distributor. | |
| Code 2 | Low Oil Pressure | ||
| Code 3 | Service Check | ||
| Code 4 | Over Crank | ||
| Code 12 | Over Voltage | ||
| Code 13 | Under Voltage | ||
| Code 14 | Over Frequency | ||
| Code 15 | Under Frequency | ||
| Code 19 | Governor Actuator | ||
| Code 22 | Governor Actuator Overload | ||
| Code 23 | Low Oil Pressure Cutoff Switch | ||
| Code 27 | Voltage Sense | ||
| Code 29 | High Battery Voltage | ||
| Code 31 | Over Speed | ||
| Code 32 | Low Cranking Speed | ||
| Code 35 | Control Card Failure | ||
| Code 36 | Engine Stopped | ||
| Code 37 | Invalid Generator Set Configuration | ||
| Code 38 | Over Current (Field Overload) |
| Symptom | Cause | Remedy |
|---|---|---|
| Genset Starts or Stops Without Command – No Fault Code | Low battery voltage, shorted harness connection, faulty start/stop switch, Auto Gen Start (AGS) is enabled | Check last fault and record; Measure battery voltage at battery and genset; Inspect battery connections and cables for cleanliness, tightness and damage: clean, tighten and repair connections and cables as necessary; Check electrolyte level and hydrometer reading in maintenance type batteries: replace electrolyte and recharge or replace battery as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for symptom: repair or replace pins in connector as necessary; Measure battery voltage at genset while attempting to start from local or remote switch: recharge or replace battery if voltage drops below 9 VDC, test and service genset battery charger if so equipped, increase battery cable size or run parallel cables; Measure battery voltage and check for charger increase while genset is running; Measure for continuity change across start/stop switch between neutral and start position and neutral and stop position at switches and at connector P1: reconnect or repair connections, replace switches as necessary; Measure for continuity from start and stop inputs to ground at switches and at connector P1: Repair or replace damaged harness; Determine if AGS is installed and enabled (AGS will command start and stop based on its own settings): disable AGS or explain AGS function to customer (see PSB-666) |
| No Response – Status Indicator Light Dead | Low/No battery voltage, poor battery connection, faulty battery, open harness connection, faulty start/stop switch, faulty LED | Measure battery voltage at battery, at genset and at connector P1: reconnect, clean, repair and replace connections as necessary; Measure battery voltage at genset while attempting to start or prime from local or remote switch: recharge or replace battery if voltage drops below 9 VDC, test and service genset battery charger if so equipped, increase battery cable size or run parallel cables; Measure for continuity change across start/stop switch between neutral and start position and neutral and stop position at switches and at connector P1: reconnect or repair connections, replace switches as necessary; Test switches LED by energizing with 12 VDC: replace switches as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for start and prime operation: replace control as necessary |
| Starting Batteries Run Down | Battery connections, battery, charging system, excessive cranking, excessive priming | Measure battery voltage at battery and genset; Inspect battery connections and cables for cleanliness, tightness and damage: clean, tighten and repair connections and cables as necessary; Check electrolyte level and hydrometer reading in maintenance type batteries: replace electrolyte and recharge or replace battery as necessary; Verify battery charger is on and check operation; Measure battery voltage and check for charging increase while genset is running; Check last fault and record: troubleshoot as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Measure for continuity change across start/stop switch between neutral and stop position at switches and P1 connector: replace switches as necessary or disconnect external stop device if so equipped; Measure for voltage at fuel pump while genset is not running or being primed: replace control as necessary |
| Starter Engages – Disengages | Battery connections, battery, charging system, start/stop switches, engine compression | Measure battery voltage at battery and genset; Inspect battery connections and cables for cleanliness, tightness and damage: clean, tighten and repair connections and cables as necessary; Check electrolyte level and hydrometer reading in maintenance type batteries: replace electrolyte and recharge or replace battery as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB–676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for fault occurrence: repair or replace pins in connector as necessary; Measure battery voltage at genset while attempting to start from local or remote switch: recharge or replace battery if voltage drops below 9 VDC, test and service genset battery charger if so equipped, increase battery cable size or run parallel cables; Measure battery voltage and check for charger increase while genset is running |
| No AC Power – Genset Running, Status LED On Steady or Flashing Rapidly | Circuit breakers, Engine Run Only mode due to faulty generator | Status light on – Measure AC output at genset circuit breaker: reset or turn on genset circuit breaker, diagnose faulty loads as necessary; HGJAD, E, F Models – (Rapid flashing status light – Engine Run Only mode): Remove connector P1 from control and re-install and try to start genset: inspect, repair or replace P1 connector pins as necessary; While running in Engine Run Only mode externally excite field with 12 VDC or 24 VDC and measure main and quadrature winding AC output; Measure field, quadrature and main winding resistance: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to ground: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Measure field, quadrature and main winding resistance to each other: clean slip rings, replace brushes, repair harness and replace rotor or stator as necessary; Check brush alignment per PSB-682a |
| Genset cranks but does not start – no fault code | Not holding start switch long enough to cause fault | Check and record last fault code; Crank genset and hold switch until control stops cranking and displays fault code (approximately 30 seconds): troubleshoot fault code and reference last fault code recorded above if necessary |
| Genset runs but stops when switch is released – no fault code | Not holding start switch long enough to cause fault | Check and record last fault code; Start genset and hold switch until control shuts down and displays fault code (approximately 30 seconds): troubleshoot fault code and reference last fault code recorded above if necessary |
| The genset does not start after two or three tries | Wait 5 seconds for the control to reset before trying again. See Section 11. Troubleshooting | |
| Status indicator light dead (genset locked out, faulty connections, no battery voltage) | Genset locked out; faulty connections; no battery voltage | Unlock the genset with the lockout switch in the cab and/or boom bucket; Try the genset Start Switch if the remote Start Switch does not work, and vice versa; Clean and tighten the positive (+) and negative (–) battery cable connections at the battery, vehicle frame and genset; Recharge or replace the battery. Refer to the battery manufacturer's recommendations. |
| Starting batteries run down (marginal batteries, connections, or charging system or, parasitic loads) | Marginal batteries; connections; charging system; parasitic loads | Clean and tighten the positive (+) and negative (–) battery cable connections at the battery, vehicle frame and genset; Recharge or replace the battery. Refer to the battery manufacturer's recommendations; Have a battery charging system installed or serviced in the vehicle. |
| Starter engages-disengages (cranking voltage dips below 6 volts—low battery charge, poor connections, long cables) | Cranking voltage dips below 6 volts; low battery charge; poor connections; long cables | Have the vehicle propulsion engine running while trying to start the genset—the battery charging alternator may be able to maintain starting voltage high enough to get the genset started; Clean and tighten the positive (+) and negative (–) battery cable connections at the battery, vehicle frame and genset; Recharge or replace the battery. Refer to the battery manufacturer's recommendations; Increase battery cable size or run parallel cables. |
| No power—genset running, status light on (line circuit breaker OFF, or tripped due to short circuit or overload) | Line circuit breaker OFF, or tripped due to short circuit or overload | Turn on or reset the line circuit breaker on the genset (Page 10); Turn on or reset the line circuit breakers on the main distribution panel in the vehicle. |
| Genset Starts or Stops Without Command — No Fault Code | Low battery voltage; shorted harness connection; faulty start/stop switch; Auto Gen Start (AGS) is enabled | Check last fault and record; Measure battery voltage at battery and genset; Inspect battery connections and cables for cleanliness, tightness and damage: clean, tighten and repair connections and cables as necessary; Check electrolyte level and hydrometer reading in maintenance type batteries: replace electrolyte and recharge or replace battery as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB-676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for symptom: repair or replace pins in connector as necessary; Measure battery voltage at genset while attempting to start from local or remote switch: recharge or replace battery if voltage drops below 9 VDC, test and service genset battery charger if so equipped, increase battery cable size or run parallel cables; Measure battery voltage and check for charger increase while genset is running; Measure for continuity change across start/stop switch between neutral and start position and neutral and stop position at switches and at connector P1: reconnect or repair connections, replace switches as necessary; Measure for continuity from start and stop inputs to ground at switches and at connector P1: Repair or replace damaged harness; Determine if AGS is installed and enabled (AGS will command start and stop based on its own settings): disable AGS or explain AGS function to customer (see PSB-666) |
| Genset Shuts Down and may restart but shuts down again — No Fault Code | Bad Plug or Not using Resistor style spark plugs | Check plug to see if it is not functioning, If so replace; Check for non-resistor spark plugs. Resistor and Non-Resistor plugs look a like except for the model numbers. Typically a resistor plug will have an "R" in the nomenclature such as W16EXR-U11 versus the non-resistor plug version W16EX-U11. Replace with Resistor Plug. The use of non-resistor plugs in place of resistor plugs in products which use magneto style ignitions and or sensitive electronic equipment can cause odd symptoms. When the spark jumps the gap it produces a significant RFI (Radio Frequency Interference) surge which can interrupt magneto ignitions and electronic controls |
| Genset Shuts Down With Fault Code — No Cause Determined | The HGJAD genset has software with an ERO (Engine Run Only) function. The set requires the control to operate the fuel injection system and a by-pass tester cannot be used to perform addition tests like a dynamic stator/rotor test | HGJAD Solution: Put 12 or 24 VDC to the brushes and check the AC output at the Q windings and the main windings; Using the chart below, determine the appropriate AC output voltages with the corresponding DC input to the field. Note: A flying short/open test may also be performed on the rotor when the set is in the ERO mode, by verifying the circuit between the brushes and ground is an open circuit. HGJAA Solution: Temporarily replace the control with the HGJAD control, part number 300-5047, and follow the HGJAD Solution located in the section above; Due to the differences in software, when the trouble shooting is complete, you must reinstall the original control to maintain proper operation and warranty status |
| No Response — Status Indicator Light Dead | Low/No battery voltage; poor battery connection; faulty battery; open harness connection; faulty start/stop switch; faulty LED | Measure battery voltage at battery, at genset and at connector P1: reconnect, clean, repair and replace connections as necessary; Measure battery voltage at genset while attempting to start or prime from local or remote switch: recharge or replace battery if voltage drops below 9 VDC, test and service genset battery charger if so equipped, increase battery cable size or run parallel cables; Measure for continuity change across start/stop switch between neutral and start position and neutral and stop position at switches and at connector P1: reconnect or repair connections, replace switches as necessary; Test switches LED by energizing with 12 VDC: replace switches as necessary; Disconnect genset control P1 connector, verify P1 pins are fully inserted and inspect pin condition per PSB-676: insert, repair or replace pins as necessary; Reconnect P1 connector and test run genset for start and prime operation: replace control as necessary |
| Starting Batteries Run Down | Battery connections; battery; charging system; excessive cranking; excessive priming | |
| Genset Cranks But Does Not Start — No Fault Code | Not holding start switch long enough to cause fault | Check and record last fault code; Crank genset and hold switch until control stops cranking and displays fault code (approximately 30 seconds): troubleshoot fault code and reference last fault code recorded above if necessary |
| Genset Runs But Stops When Switch Is Released — No Fault Code | Not holding start switch long enough to cause fault | Check and record last fault code; Start genset and hold switch until control shuts down and displays fault code (approximately 30 seconds): troubleshoot fault code and reference last fault code recorded above if necessary |
| STATUS INDICATOR LIGHT DEAD | Genset locked out, faulty connections, no battery voltage | Unlock the genset with the lockout switch in the cab and/or boom bucket; Try the genset Start Switch if the remote Start Switch does not work, and vice versa; Clean and tighten the positive (+) and negative (-) battery cable connections at the battery, vehicle frame and genset; Recharge or replace the battery. Refer to the battery manufacturer's recommendations. |
| STARTING BATTERIES RUN DOWN | Marginal batteries, connections, or charging system or, parasitic loads | Clean and tighten the positive (+) and negative (-) battery cable connections at the battery, vehicle frame and genset; Recharge or replace the battery. Refer to the battery manufacturer's recommendations; Have a battery charging system installed or serviced in the vehicle. |
| STARTER ENGAGES-DISENGAGES | Cranking voltage dips below 6 volts—low battery charge, poor connections, long cables | Have the vehicle propulsion engine running while trying to start the genset—the battery charging alternator may be able to maintain starting voltage high enough to get the genset started; Clean and tighten the positive (+) and negative (-) battery cable connections at the battery, vehicle frame and genset; Recharge or replace the battery. Refer to the battery manufacturer's recommendations; Increase battery cable size or run parallel cables. |
| NO POWER—GENSET RUNNING, STATUS LIGHT ON | Line circuit breaker OFF, or tripped due to short circuit or overload | Turn on or reset the line circuit breaker on the genset (Page Section 3.10); Turn on or reset the line circuit breakers on the main distribution panel in the vehicle. |
| Status Indicator Not Working — Indicates that there could be faulty connections or no battery voltage. | Faulty connections; no battery voltage. | Try the generator set control switch if the remote control switch start doesn't work, and vice versa; clean and tighten the positive (+) and negative (–) battery cable connections at the battery and at the generator set; recharge or replace the battery (refer to the battery manufacturer's recommendations). |
| Starting Batteries Run Down — Indicates problem with batteries, connections, charging system, or parasitic loads. | Batteries, connections, charging system, or parasitic loads. | Clean and tighten the positive (+) and negative (–) battery cable connections at the battery and at the generator set; recharge or replace the battery (refer to the battery manufacturer's recommendations); install or service a battery charging system in the vehicle. |
| Starter Engages-Disengages — Indicates cranking voltage dips below 6 Volts. | Cranking voltage dips below 6 Volts. | Run the vehicle propulsion engine while trying to start the generator set—the battery charging alternator may be able to maintain starting voltage high enough to start the generator set; clean and tighten the positive (+) and negative (–) battery cable connections at the battery and at the generator set; recharge or replace the battery (refer to the battery manufacturer's recommendations); increase battery cable size or run parallel cables. |
| No Power—Generator Set Running, Status Light On — Indicates line circuit breaker is OFF, or tripped due to short circuit or overload. | Line circuit breaker is OFF, or tripped due to short circuit or overload. | Turn on or reset the line circuit breaker on the generator set; turn on or reset the line circuit breaker on the main distribution panel in the vehicle. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: Microprocessor ROM error during self-test; Microprocessor RAM error during self-test; Microprocessor malfunction. See the table for the matching fixes.
Documented causes: Prime mode exceeded 3 minutes; While running, EGT temp falls below 60C (140F) for 2 minutes - OR - if EGT temperature is not above 60C (140F) after 2 minutes from starting, set will shut down; (Prime mode exceeded 3 minutes). See the table for the matching fixes.
Documented causes: Exhaust gas temperatures reach 650C (1202F) for 2 secs when the set is running; With the set running and/or startup - control reads 1000C (1832F) for 1 second; (Exhaust gas temperatures reach 650C (1202F) for 2 secs when the set is running). See the table for the matching fixes.