Cummins/Onan GSBB troubleshooting: 21 fault codes and 10 symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan GSBB — 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; faulty 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 the generator set control J1 connector. Verify that the J1 pins are fully inserted and inspect pin condition, then insert, repair, or replace pins as necessary; Reconnect the J1 connector and test run the generator set for fault occurrence: repair or replace pins in the connector as necessary; Measure continuity change across the start/stop switch between rest and under simulated pressure: replace the switch as necessary; Measure continuity between ground and J1-6: repair or replace the harness as necessary; Measure oil pressure with a mechanical gauge: repair or replace the 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; You can read the fault code from the in-home Operator Panel if access is granted |
| 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 the start/stop switch between the neutral and start position at the switches and the J1 connector: replace switches as necessary or disconnect the external start device if so equipped; Disconnect the generator set control J1 connector, verify the J1 pins are fully inserted, and inspect pin condition: insert, repair, or replace pins as necessary; Reconnect the J1 connector and test run the generator set for fault occurrence: repair or replace pins in the connector as necessary; Verify engine rotation manually: repair engine damage as necessary; Measure DC voltage at the starter during start attempt: repair wire connections, replace the start solenoid and starter as necessary; Check air filter cleanliness; replace the air filter as necessary; Check for blocked or damaged exhaust system: repair or replace exhaust components 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; Run the generator set on shop fuel supply; verify tank level and fuel line condition; Measure steady DC voltage at the fuel solenoid while the generator set is running; repair wiring as necessary; Verify clear vent hose; Check the generator set fuel lines for damage: replace the fuel line as required; Measure the fuel supply and regulator lock-off pressures; Check the governor, actuator, linkage, and spring for debris, damage, and looseness: readjust and repair as necessary; Verify that the spark plug cables are secure on the spark plugs: reconnect or replace as necessary; Inspect the ignition kill lead (J1-12) in the harness and at connector J1: repair or replace the lead, terminal, or pins as necessary; Measure the spark plug gap: set the gap or replace the spark plugs as necessary; Verify the ignition spark condition; Inspect the spark plug leads, kill lead terminals at magnetos, and measure magneto air gap: replace the terminals, set the gap, or replace the magnetos as necessary; Measure field, quadrature, and main winding resistance: clean the slip rings, replace the brushes, repair the harness, and replace the rotor or stator as necessary; Measure field, quadrature, and main winding resistance to ground: clean the slip rings, replace the brushes, repair the harness, and replace the rotor or stator as necessary; Measure field, quadrature, and main winding resistance to each other: clean the slip rings, replace the brushes, repair the harness, and replace the rotor or stator as necessary; Check the alignment of the brushes to the slip rings |
| 12 | Overvoltage | Generator set loads; wire connections; windings | Verify that Last Fault is FC 12: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure and verify AC voltage at the customer connection block and at pins J1-34 and J1-35; Measure and verify AC frequency while changing engine rpm to determine if frequency response matches engine rpm response; Cycle loads to determine if a particular load causes fault: diagnose faulty load as necessary; Verify balanced loads in 120/240 VAC applications: balance loads within 10 percent line-to-line as required; Remove connector J1 from the control and re-install, and try to start the generator set: inspect, repair, or replace the J1 connector pins as necessary; Measure field, quadrature, and main winding resistance: clean the slip rings, replace the brushes, repair the harness, and replace the rotor or stator as necessary; Measure field, quadrature, and main winding resistance to ground: clean the slip rings, replace the brushes, repair the harness, and replace the rotor or stator as necessary; Measure field, quadrature, and main winding resistance to each other: clean the slip rings, replace the brushes, repair the harness, and replace the rotor or stator as necessary; Check the alignment of the brushes to the slip rings |
| 13 | Undervoltage | Generator set loads; wire connections; windings | Verify that the Last Fault is FC 13: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure and verify AC voltage at the customer connection block and at pins J1-34 and J1-35; Measure and verify AC frequency while changing engine rpm to determine if frequency response matches engine rpm response; Cycle loads to determine if a particular load will cause fault: diagnose faulty load as necessary; Verify balanced loads in 120/240 VAC applications: balance loads within 10 percent line-to-line as required; Remove connector J1 from the control and re-install it, and try to start the generator set: inspect, repair, or replace J1 connector pins as necessary; Measure field, quadrature and main winding resistance: clean the slip rings, replace the brushes, repair the harness, and replace the rotor or stator as necessary; Measure field, quadrature, and main winding resistance to ground: clean the slip rings, replace the brushes, repair the harness, and replace the rotor or stator as necessary; Measure field, quadrature, and main winding resistance to each other: clean the slip rings, replace the brushes, repair the harness, and replace the rotor or stator as necessary; Check brush alignment: Inspect brush wear on the slip rings and verify brush misalignment is toward the windings |
| 14 | Overfrequency — Instantaneous Fault - Frequency greater than 72Hz Delayed Fault - Frequency greater than 66Hz, but less than 72Hz, for 6 continuous seconds | Generator set loads; engine governor function; fuel supply; air fuel mixture; exhaust system; choke; demand regulator; carburetor; generator windings; wire connections | Verify that the Last Fault is FC 14: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure AC current while running the generator set with loads: identify faulty or short cycling loads; Measure generator set load capability with load bank (de-rate for altitude and temperature as necessary); Measure AC frequency while running; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response; Disconnect the generator set control J1 connector, verify the J1 pins are fully inserted, and inspect pin condition using the tester tool #420-0603 and a mating pin connector or pin gauge of the same size (.045"): insert, repair, or replace pins as necessary; Reconnect J1 connector and test run the generator set for fault occurrence: repair or replace pins in the connector as necessary; Check all grounds and neutral leads for looseness at the battery and the generator set; run the generator set on a separate battery: tighten or replace terminals and leads as necessary; Check for air filter cleanliness; replace air filter as necessary; Check for blocked or damaged exhaust system: repair or replace exhaust components 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; Run the generator set on shop fuel supply; verify the tank level and fuel line condition; Measure steady DC voltage at the fuel solenoid while the generator set is running; repair wiring as necessary; Verify clear vent hose; Check the generator set fuel lines for damage: replace the fuel line as required; Measure fuel supply and regulator lock off pressures; Check the governor, actuator, linkage, and spring for debris, damage, and looseness: readjust and repair as necessary; Measure field, quadrature, and main winding resistance: clean the slip rings, replace the brushes, repair the harness, and replace the 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 the slip rings, replace the brushes, repair the harness, and replace the rotor or stator as necessary; Check brush alignment: inspect brush wear on the slip rings and verify brush misalignment is toward the windings; if misalignment is toward the bearing, the cause is not from this tolerance issue and is likely the result of the end bell not being seated properly during assembly; inspect for cause and repair as necessary; Verify that spark plug cables are secure on spark plugs: reconnect or replace as necessary; Inspect ignition kill lead (J1-12) in harness and at connector J1: repair or replace lead, terminal or pins as necessary; Measure spark plug gap: set the gap or replace the spark plugs as necessary; Verify ignition spark condition; Inspect the spark plug leads, kill lead terminals at magnetos, and measure magneto air gap: replace the terminals, set the gap, or replace magnetos as necessary |
| 15 | Underfrequency — Frequency less than 54 Hz (for the 60 Hz model) or 45 Hz (for the 50 Hz model) for 8 continuous seconds | Generator set loads; engine governor function; fuel supply; air fuel mixture; exhaust system; choke; demand regulator; carburetor; generator windings; ignition; wire connections | Verify that the Last Fault is FC 15: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure AC current while running the generator set with loads: identify faulty or short cycling loads; Measure generator set load capability with shop load bank (de-rate for altitude and temperature as necessary); Measure AC frequency; Disconnect the generator set control J1 connector, verify the J1 pins are fully inserted, and inspect pin condition using the tester tool #420-0603 and a mating pin connector or pin gauge of the same size (.045"): insert, repair, or replace the pins as necessary; Reconnect the J1 connector and test run the generator set for fault occurrence: repair or replace pins in the connector as necessary |
| 22 | Governor Actuator Overload — Maximum governor output (PWM) for 10 continuous seconds while fuel pressure switch open and current at 100% | Generator set loads; wire connections; fuel supply; air fuel mixture; exhaust system; governor actuator; ignition system | Verify that the Last Fault is FC 22: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure AC current while running the generator set with loads: identify faulty or short cycling loads or reduce loads as necessary; Measure the generator set load capability with a shop load bank (de-rate for altitude and temperature as necessary); Measure AC frequency and droop while the generator set is running; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response; Disconnect the generator set control J1 connector, verify J1 pins are fully inserted, and inspect pin condition using the tester tool #420-0603 and a mating pin connector or pin gauge of the same size (.045"): insert, repair, or replace pins as necessary; Reconnect the J1 connector and test run the generator set for fault occurrence: repair or replace pins in the connector as necessary; Check air filter cleanliness; replace the air filter as necessary; Measure steady DC voltage at the fuel solenoid while the generator set is running; repair wiring 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; Run generator set on shop fuel supply; verify tank level and fuel line condition; Verify clear vent hose; Check the generator set fuel lines for damage: replace the fuel line as required; Measure the regulator lock off pressure; Check the intake manifold and gaskets for air leaks: tighten fasteners and replace the gaskets and manifold as necessary; Check for a blocked or damaged exhaust system: repair or replace the exhaust components as necessary; Verify actuator function by applying DC voltage to the terminals: replace the actuator as necessary; Check the carburetor for binding; inspect the spring for dirt and debris: clean the spring, replace the carburetor as necessary; Verify that spark plug cables are secure on the spark plugs: reconnect or replace as necessary; Inspect the ignition kill lead (J1-12) in the harness and at connector J1: repair or replace the lead, terminal, or pins as necessary; Measure spark plug gap: set gap or replace spark plugs as necessary; Verify ignition spark condition; Inspect the spark plug leads, kill lead terminals at magnetos, and measure the magneto air gap: replace the terminals, set the gap, or replace the magnetos as necessary |
| 27 | Voltage Sense Lost — generator set frequency is greater than 40 Hz and voltage sensed less than 5 VAC on one or both lines. (The control senses if one line is lost or disconnected) | Generator set loads; generator windings; ignition; wire connections | Verify that the Last Fault is FC 27: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure AC voltage; Disconnect the generator set control J1 connector, verify the J1 pins are fully inserted, and inspect pin condition using the tester tool #420-0603 and a mating pin connector or pin gauge of the same size (.045"): insert, repair, or replace pins as necessary; Reconnect the J1 connector and test run the generator set for fault occurrence: repair or replace pins in the connector as necessary; Measure field, quadrature, and main winding resistance: clean the slip rings, replace the brushes, repair the harness, and replace the rotor or stator as necessary; Measure field, quadrature, and main winding resistance to ground: clean the slip rings, replace the brushes, repair the harness, and replace the rotor or stator as necessary; Measure field, quadrature, and main winding resistance to each other: clean the slip rings, replace the brushes, repair the harness, and replace the rotor or stator as necessary; Check brush alignment; Verify that the spark plug cables are secure on the spark plugs: reconnect or replace as necessary; Inspect the ignition kill lead (J1-12) in the harness and at connector J1: repair or replace the lead, the terminal, or the pins as necessary; Measure the spark plug gap: set the gap or replace the spark plugs as necessary; Verify ignition spark condition; Inspect the spark plug leads, kill lead terminals at magnetos, and measure the magneto air gap: replace the terminals, set the gap, or replace the magnetos as necessary; Measure temperature of the air intake and temperature rise across the generator set; remove blockage or prevent air recirculation |
| 29 | High Battery Voltage — DC voltage to controller greater than 19 VDC | Incorrect battery configuration; wire damage; faulty charger; control | Verify that the Last Fault is FC 29: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure DC voltage at the battery, at the generator set, and at connector J1: reconnect the battery or repair wiring as necessary; Measure DC voltage with the battery charger on: reduce the boost charge rate or diagnose the faulty charger as necessary; Disconnect the generator set control J1 connector, verify that the J1 pins are fully inserted, and inspect pin condition using the tester tool #420-0603 and a mating pin connector or pin gauge of the same size (.045"): insert, repair, or replace pins as necessary; Reconnect the J1 connector and test run the generator set for fault occurrence |
| 32 | Low Cranking Speed Sense — Quadrature frequency less than 1Hz (Engine RPM less than 180) for 3 continuous seconds after pressing start | Starter; engine components; air intake system; exhaust system; generator windings; wire connections; battery; battery connections; oil viscosity | Verify that the Last Fault is FC 32: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure battery voltage at the battery and the generator set: recharge or replace the battery as necessary; Verify engine rotation manually: repair engine damage as necessary; Verify generator rotation manually: repair generator damage as necessary; Disconnect the generator set control J1 connector, verify that the J1 pins are fully inserted, and inspect pin condition using the tester tool #420-0603 and a mating pin connector or pin gauge of the same size (.045"): insert, repair, or replace pins as necessary; Reconnect the J1 connector and test run the generator set for fault occurrence: repair or replace pins in the connector as necessary; Measure DC voltage at the starter during a start attempt: repair wire connections, replace the start solenoid and starter as necessary; Check air filter cleanliness; replace the air filter as necessary; Check for a blocked or damaged exhaust system: repair or replace exhaust components as necessary; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response; 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; Run the generator set on shop fuel supply; verify tank level and fuel line condition; Measure steady DC voltage at the fuel solenoid while the generator set is running; repair wiring as necessary; Verify clear vent hose; Check the generator set fuel lines for damage: replace fuel line as required; Measure fuel supply and regulator lock off pressures; Check the governor, actuator, linkage, and spring for debris, damage, and looseness: readjust and repair as necessary; Verify that the spark plug cables are secure on the spark plugs: reconnect or replace as necessary; Inspect the ignition kill lead (J1-12) in the harness and at connector J1: repair or replace the lead, terminal, or pins as necessary; Measure the spark plug gap: set the gap or replace the spark plugs as necessary; Verify ignition spark condition; Inspect the spark plug leads, kill lead terminals at magnetos, and measure the magneto air gap: replace the terminals, set the gap, or replace the magnetos as necessary; Measure the temperature of the air intake and temperature rise across the generator set; remove blockage or prevent air recirculation |
| 35 | Control Card Failure — EEPROM (programming variables) error during self test | Faulty program | Verify that the Last Fault is FC 35: Yes, continue diagnosis; No, troubleshoot actual last fault; Replace the control |
| 36 | Generator Set Stopped Without Fault Condition — RPM less than 500 and Sense Voltage S1-S2 at 0 VAC while fuel pressure switch open and no other fault condition occurred | Fuel supply; air fuel mixture; exhaust system; choke; demand regulator; carburetor; generator windings; ignition; wire connections | Verify that the Last Fault is FC 36: Yes, continue diagnosis; No, troubleshoot actual last fault; Verify engine rotation manually: repair engine damage as necessary; Verify generator rotation manually: repair generator damage as necessary; Disconnect the generator set control J1 connector, verify that the J1 pins are fully inserted, and inspect pin condition using the tester tool #420-0603 and a mating pin connector or pin gauge of the same size (.045"): insert, repair, or replace pins as necessary; Reconnect the J1 connector and test run the generator set for fault occurrence: repair or replace pins in the connector as necessary; Check the air filter for cleanliness; replace air filter as necessary; Check for a blocked or damaged exhaust system: repair or replace exhaust components as necessary; Measure the generator set load capability with a shop load bank; Measure AC frequency while changing engine rpm to determine if frequency response matches engine rpm response; 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; Run the generator set on shop fuel supply; verify the tank level and fuel line condition; Measure steady DC voltage at the fuel solenoid while the generator set is running; repair wiring as necessary; Verify clear vent hose; Check the generator set fuel lines for damage: replace fuel lines as required; Measure the fuel supply and regulator lock off pressures; Check the governor, actuator, linkage, and spring for debris, damage, and looseness: readjust and repair as necessary; Verify that the spark plug cables are secure on the spark plugs: reconnect or replace as necessary; Inspect ignition kill lead (J1-12) in harness and at connector J1: repair or replace the lead, terminal, or pins as necessary; Measure the spark plug gap: set the gap or replace the spark plugs as necessary; Verify ignition spark condition; Inspect the spark plug lead, kill lead terminals at magnetos, and measure the magneto air gap: replace the terminals, set the gap, or replace the magnetos as necessary; Measure temperature of the air intake and temperature rise across the generator set; remove blockage or prevent air recirculation |
| 37 | Invalid Set Configuration — Generator set control configuration does not meet any valid configuration | Generator set configuration; control | Verify that the Last Fault is FC 37: Yes, continue diagnosis; No, troubleshoot actual last fault; Using the remote display, reset and save the generator set configuration; If the generator set configuration is correct and the fault will not clear, replace the control |
| 43 | Processor Fault — RAM (programming variables) error during self test | Faulty program | Verify that the Last Fault is FC 43: Yes, continue diagnosis; No, troubleshoot actual last fault; Disconnect battery power to the generator set control, wait 30 seconds, and reconnect the battery. Power up control and verify if fault code returns; Replace the control |
| 45 | Speed Sense Fault — While running quadrature frequency dropped to 0 Hz for 1 continuous second | Loads; generator windings; wire connections | Verify that the Last Fault is FC 45: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure quadrature winding resistance at stator leads (J1-2 and J1-3) and at the J1 connector; Disconnect the generator set control J1 connector, verify that the J1 pins are fully inserted, and inspect pin condition using the tester tool #420-0603 and a mating pin connector or pin gauge of the same size (.045"): insert, repair, or replace pins as necessary; Reconnect the J1 connector and test run the generator set for fault occurrence: repair or replace pins in the connector as necessary; Measure AC current while running the generator set with loads: identify faulty or short cycling loads; Measure generator set load capability with a shop load bank (de-rate for altitude and temperature as necessary); Measure generator set frequency and droop while running; Measure AC frequency while changing the engine rpm to determine if the frequency response matches engine rpm response: repair the damaged generator drive system as necessary |
| 46 | Generator Set Overload — Current is at or above operational design limit and approaching fault declaration: 13, 15, 22, or 36 | Loads; wire connections; windings | Verify that the Last Fault is FC 46: Yes, continue diagnosis; No, troubleshoot actual last fault; Measure AC current and voltage while running the generator set with loads: identify faulty or short cycling loads or reduce loads as necessary; Measure the generator set load capability with a shop load bank (de-rate for altitude and temperature as necessary); Disconnect the generator set control J1 connector, verify that the J1 pins are fully inserted, and inspect pin condition using the tester tool #420-0603 and a mating pin connector or pin gauge of the same size (.045"): insert, repair, or replace pins as necessary; Reconnect the J1 connector and test run the generator set for fault occurrence: repair or replace pins in the connector as necessary; Check the air filter for cleanliness; replace the air filter as necessary; Measure steady DC voltage at the fuel solenoid while the generator set is running; repair wiring as necessary; Verify clear vent hose; Run the generator set on shop fuel supply; verify the tank level and fuel line condition; Check the generator set fuel lines for damage: replace the fuel lines as required; Measure regulator lock off pressure; Check the intake manifold and gaskets for air leaks: tighten the fasteners and replace the gaskets and manifold as necessary; Check for a blocked or damaged exhaust system: repair or replace exhaust components as necessary; Verify actuator function by applying DC voltage to the terminals: replace the actuator as necessary; Check the carburetor for binding; inspect the spring for dirt and debris: clean the spring; replace the carburetor as necessary; Verify that the spark plug cables are secure on the spark plugs: reconnect or replace as necessary; Inspect ignition kill lead (J1-12) in the harness and at connector J1: repair or replace the lead, terminal, or pins as necessary; Measure the spark plug gap: set the gap or replace the spark plugs as necessary; Verify ignition spark condition; Inspect the spark plug leads, kill lead terminals at magnetos, and measure the magneto air gap: replace the terminals, set the gap, or replace the magnetos as necessary |
| 76 | Alternator Over Temp — Temperature at alternator is too high (switch at 170 °F) | Wire connections; faulty temperature sensor; faulty DC fan; blocked intake or exhaust openings | Verify that the Last Fault is FC 76: Yes, continue diagnosis; No, troubleshoot actual last fault; Verify the generator set enclosure is fully closed and latched during operation to promote proper air flow; Verify the generator set enclosure for clear intake and exhaust openings; Verify the temperature at the customer connection terminal block within the generator set; Disconnect the generator set control J1 connector, verify that the J1 pins are fully inserted and inspect pin condition using the tester tool #420-0603 and a mating pin connector or pin gauge of the same size (.045"): insert, repair, or replace pins as necessary; Verify the temperature sensor resistance. Replace as necessary; Measure the temperature sensor wiring (J1-33) for continuity. Repair or replace as necessary; Visually inspect the alternator fan for missing or damaged fins. Replace the fan if necessary |
| 78 | Low Fuel Pressure — Controller sensed fuel pressure switch open and approaching fault declaration: 14, 15, 22 or 36 | Wire connections; fuel system; fuel pressure switch | Verify that the Last Fault is FC 78: Yes, continue diagnosis; No, troubleshoot actual last fault; Verify the fuel supply and regulator lock off pressures; Measure steady DC voltage at the fuel solenoid while the generator set is running; repair wiring as necessary; Verify the fuel lines are not kinked or broken/cracked; Run the generator set on shop fuel supply; verify the tank level and fuel line condition; Check the generator set fuel lines for damage: replace the fuel line as required; Check for fuel pressure switch continuity to ground while the generator set is running; Check for fuel pressure switch continuity across its terminals while fuel system pressure is applied; Check the fuel pressure switch wiring for an open circuit; Disconnect the generator set control J1 connector, verify that the J1 pins are fully inserted and inspect pin condition using the tester tool #420-0603 and a mating pin connector or pin gauge of the same size (.045"): insert, repair, or replace pins as necessary |
| 79 | Failure To Transfer To Generator Set — Controller commanded transfer switch to standby position but standby position feedback not received after the 5 second transfer time delay | Wire connections; faulty positional switch; faulty transfer switch component(s) | Verify that the main AC circuit breaker on generator set is to "On"; Verify that the Last Fault is FC 79: Yes, continue diagnosis; No, troubleshoot actual last fault; Manually start an exercise session and verify the transfer switch position during the exercise; Disable the generator by placing the generator local start switch in the "Off" position; Manually operate the transfer switch via lever to the generator position; check for generator position switch continuity to ground at the transfer switch; Check for continuity from the transfer terminal block position (TB4-6) to the generator position terminal (J2-5); Check for a ground signal at the generator position terminal (J2-5) at the control connector; repair wiring as necessary; Disconnect the generator set control J1 connector, verify that the J1 pins are fully inserted and inspect pin condition using the tester tool #420-0603 and a mating pin connector or pin gauge of the same size (.045"): insert, repair, or replace pins as necessary |
| 19 | Governor Actuator Shutdown |
| Symptom | Cause | Remedy |
|---|---|---|
| Generator Set Starts or Stops Without Command - No Fault Code | Low battery voltage; shorted harness connection; faulty start/stop switch; "Standby Ready" is enabled; faulty or incorrect spark plugs | Check last fault and record; Measure battery voltage at battery and generator set; 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 generator set control J1 connector. Verify that the J1 pins are fully inserted and inspect pin condition, then insert, repair or replace pins as necessary; Reconnect J1 connector and test run generator set for symptom: repair or replace pins in connector as necessary; Measure battery voltage at generator set while attempting to start from local or remote switch: recharge or replace battery if voltage drops below 8 VDC, test and service generator set battery charger; Measure battery voltage and check for voltage increase while generator set 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 J1: reconnect or repair connections, replace switches as necessary; Measure for continuity from start and stop inputs to ground at switches and at connector J1: Repair or replace damaged harness; Determine if "Standby Ready" is enabled: disable "Standby Ready" or explain "Standby Ready" function to customer; Verify the condition of the spark plugs and whether they are Cummins Onan branded plug(s). Replace the spark plug(s) if questionable or of non-Cummins Onan origin |
| No Response - Status Indicator Light Dead | Low/No battery voltage; poor battery connection; faulty battery; open harness connection; faulty start/stop switch; faulty LED; F3 fuse open | Measure the battery voltage at the battery, at the generator set, and at connector J1: reconnect, clean, repair, and replace connections as necessary; Measure battery voltage at the generator set while attempting to start or prime from the local or remote switch: recharge or replace the battery if voltage drops below 8 VDC, test and service the generator set battery charger if so equipped, increase battery cable size or run parallel cables; Check F3 fuse for open circuit; Measure for continuity change across start/stop switch between neutral and start position and neutral and stop position at switches and at connector J1: reconnect or repair connections; replace switches as necessary; Test switches LED by energizing with 12 VDC: replace switches as necessary; Disconnect the generator set control J1 connector. Verify that the J1 pins are fully inserted and inspect pin condition, then insert, repair, or replace pins as necessary; Reconnect the J1 connector and test run the generator set for start operation |
| Starting Battery Runs Down | Marginal battery connections; battery; charging system; excessive cranking | Measure battery voltage at the battery and the generator set; 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 the battery as necessary; Verify the battery charger is on and check operation; Measure battery voltage and check for voltage increase while the generator set is running; Check last fault and record: troubleshoot as necessary; Disconnect the generator set control J1 connector. Verify that the J1 pins are fully inserted and inspect pin condition, then insert, repair, or replace pins as necessary; Reconnect the J1 connector and test run the generator set for fault occurrence: repair or replace pins in the connector as necessary; Measure for continuity change across the start/stop switch between the neutral and stop position at the switches and the J1 connector: replace switches as necessary or disconnect the external stop device if so equipped; Measure for voltage at the fuel solenoid while the generator set is not running |
| Starter Engages - Disengages | Battery connections; battery; charging system; start/stop switches; engine compression; faulty or incorrect spark plugs | Measure battery voltage at the battery and the generator set; Inspect the 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 the battery as necessary; Disconnect the generator set control J1 connector. Verify that the J1 pins are fully inserted and inspect pin condition, then insert, repair, or replace pins as necessary; Reconnect the J1 connector and test run the generator set for fault occurrence: repair or replace pins in the connector as necessary; Measure battery voltage at the generator set while attempting to start from a local or remote switch: recharge or replace the battery if voltage drops below 8 VDC, test and service the generator set battery charger if so equipped, increase the battery cable size or run parallel cables; Verify the condition of the spark plugs and whether they are Cummins Onan branded plugs. Replace the spark plug(s) if questionable or of non-Cummins Onan origin; Measure battery voltage and check for voltage increase while the generator set is running |
| No AC Power - Generator Set Running, Status LED On Steady or Flashing Rapidly | Circuit breakers; customer loads | Status light on - Measure AC output at generator set circuit breaker: reset or turn on the generator set circuit breaker; diagnose faulty loads as necessary |
| Generator Set Cranks But Does Not Start - No Fault Code | Faulty or incorrect spark plugs; low battery output; low fuel pressure | Check and record last fault code; Measure battery voltage at the battery and the generator set; Inspect the 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 the battery as necessary; Check the fuel supply pressure coming into the generator regulator and ensure it is within specification; Verify the condition of the spark plugs and whether they are Cummins Onan branded plug(s). Replace the spark plug(s) if questionable or of non-Cummins Onan origin |
| Genset Warning - Transfer Switch Failed to Transfer Back to Utility When Utility is Restored - No Fault Code | Transfer switch is faulty, or wire is disconnected or broken | Fix wire connection; Replace a broken wire; Replace a faulty transfer switch |
| In-Home Network Access to Generator Set Troubleshooting | Bad connections or bad communications | Check connections: verify that the Ethernet cable is plugged into the generator set control and the router; verify that the computer that is attempting to access the generator set is connected to the same router as the generator set via an Ethernet cable (on the same local area network); verify that the wireless card on the computer is turned off; check to see if both ends of the Ethernet cable are assembled and crimped as described in the installation instructions. If not, reassemble and crimp as described in the installation instructions; verify that the Ethernet cable connections between the generator set and the router are solid and correct; proceed to "Check communications"; Check communications: if the router is also connected to an incoming connection from an ISP, check to see if you can access a standard web page with the computer connected to the same router as the generator set. If not, contact your router manufacturer for troubleshooting information; check to see if the green and orange lights are illuminated at the Ethernet connection port on the generator set control board. If the lights are not illuminated, this indicates that no information is being transmitted or received. Test the cable by disconnecting the Ethernet cable from the generator control board and connecting it to the computer (swap the cable with the existing Ethernet cable). With the router connected to the ISP, check to see if you can access a standard web page. If you can access a standard web page, call Cummins Support at 1-800-888-6626 and select option 1. If you cannot access a standard web page, go to the "Check connections" step above; check to see if the correct generator IP address has been entered. If not, enter the correct IP address in the address bar of the web browser. Be sure to not enter "www" or other text prior to the IP address; if none of the above troubleshooting techniques help, call Cummins Support at 1-800-888-6626 and select option 1 |
| Remote Internet Access to Generator Set Troubleshooting | Improper setup; no high-speed internet connection; public IP address is not active or properly set up; incorrect IP address is entered; computer is connected to the same router or network as the generator set; or the internet connection is faulty | Check to see if you are able to access the generator set with your in-home computer. If not, refer to the In-Home Network Access Troubleshooting procedures; Verify that you followed the network setup procedures. Refer to the Network Setup Guide; Verify that you are using a high-speed internet connection; Verify that the public IP address is active and set up properly with the ISP (Internet Service Provider). If necessary, contact the ISP to verify your setup; Verify that the correct public IP address is entered into the web browser of the computer (i.e. xxx.xxx.xxx.xxx); Verify that the computer is not connected to the same router or local area network as the generator set. If it is on the same network, you will be able to access the generator set using the local network IP address configured on the generator set. The computer used for internet access must be connected to a different internet connection than the generator set; Check to see if you can access a standard web page from a computer. If not, contact the ISP to troubleshoot the internet connection; Verify all settings, as described in the Network Setup Guide; If the previous steps do not correct the problem, contact a computer network specialist to diagnose |
| Email Alert Troubleshooting | An improper setup; the alert level is not set to "all events"; emails cannot be received; the outgoing email address is not included in your contact list; the email account is not capable of using plain SMTP for the outgoing SMTP server setup; the domain name is not included in the user name field of the Network Setup screen; or the DNS #1 and #2 values are incorrect on the Network Setup screen | Check to see if you are able to access the generator set with your in-home computer. If not, refer to In-Home Computer Access Troubleshooting; Verify that you followed the network setup instructions. Refer to the Network Setup Guide; Verify that the alert level is set to All Events: to verify that your generator set can send emails, select Disable Standby and wait several minutes to verify that you did receive an email; select Enable Standby and wait a few more minutes to verify that you did receive a second email; Send an email to the destination email address and check to see if you received this email. If not, contact your email service provider or your ISP (Internet service provider) to diagnose; Check to see if the destination email accounts have spam filtering: if spam filtering is present, add the outgoing email address to your contact list; if spam filtering is not present, proceed to step 6; Ensure that the SMTP server in use is capable of distributing non SSL certified emails. If the SMTP server is not capable of sending non SSL certified emails or the status is unknown, please contact your ISP technical support for information; Verify that the domain name is included in the user name field of the Network Setup screen (i.e. username@domainname); Verify with your ISP that the Static DNS (Domain Name Server) #1 and #2 are correct; If the previous steps do not correct the problem, contact a computer network specialist to diagnose |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: Low battery voltage; shorted harness connection; faulty start/stop switch; "Standby Ready" is enabled; faulty or incorrect spark plugs. See the table for the matching fixes.
Documented causes: Low/No battery voltage; poor battery connection; faulty battery; open harness connection; faulty start/stop switch; faulty LED; F3 fuse open. See the table for the matching fixes.
Documented causes: Marginal battery connections; battery; charging system; excessive cranking. See the table for the matching fixes.