Cummins/Onan 7.0 HGJAD troubleshooting: 67 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan 7.0 HGJAD — full specs, parts & maintenance.
All Cummins/Onan fault codes →
| Code | Meaning | Cause | Remedy |
|---|---|---|---|
| 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 | Corrective Action: 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. | |
| 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 | Corrective Action: 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. | |
| 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 | Corrective Action: 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.) | |
| 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 | ||
| 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 | Corrective Action: 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.) | |
| 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) | 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 Fault | ||
| 3 | Service Check Fault | ||
| 4 | Overcrank | ||
| 12 | Overvoltage | ||
| 13 | Undervoltage | ||
| 14 | Overfrequency | ||
| 15 | Underfrequency | ||
| 17 | Fuel Pump Fault | ||
| 19 | Governor Actuator (EFI Only) | ||
| 22 | Governor Actuator Overload (EFI Only) | ||
| 23 | Oil Pressure Switch Fault | ||
| 27 | Voltage Sense Lost | ||
| 29 | High Battery Voltage | ||
| 31 | Overspeed Fault (HGJAD, E, F Models Only) | ||
| 32 | Low Cranking Speed Sense | ||
| 33 | Fault Code 33 | ||
| 35 | Control Card Failure | ||
| 36 | Genset Stopped Without Fault Condition | ||
| 37 | Invalid Set Configuration | ||
| 38 | Field Overload (Overvoltage) | ||
| 41 | Generator Rotor Fault | ||
| 42 | Processor Fault | ||
| 45 | Speed Sense Fault | ||
| 47 | Ignition Fault | ||
| 48 | Field Sense Fault | ||
| 51 | Processor Failure | ||
| 52 | Fuel Injector Fault | ||
| 54 | MAT Sensor Fault | ||
| 56 | MAP Sensor Fault | ||
| 57 | Overprime Fault | ||
| CODE NO. 52 | FUEL INJECTOR SHUTDOWN—Open or short circuit in fuel injector | Corrective Action: See an authorized Onan dealer. | |
| 2 | LOW OIL PRESSURE SHUTDOWN—CODE NO. 2 | 1. Check engine oil level and add oil as necessary (Page 17). 2. Drain excess oil (above dipstick Full mark.) | |
| 3 | SERVICE CHECK SHUTDOWN—CODE NO. 3 | 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—CODE NO. 4 | 1. 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.) 2. Prime the engine fuel system by holding the control switch at Stop/Prime for 30 seconds. 3. 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. 4. Open any closed fuel valves. 5. Secure the spark plug leads on the spark plugs (Page 20). 6. Replace the spark p |
| Symptom | Remedy |
|---|---|
| STATUS INDICATOR LIGHT DEAD (Genset locked out, faulty connections, no battery voltage) | 1. Unlock the genset with the lockout switch in the cab and/or boom bucket. 2. Try the genset Start Switch if the remote Start Switch does not work, and vice versa. 3. Clean and tighten the positive (+) and negative (-) battery cable connections at the battery, vehicle frame and genset. 4. 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) | 1. Clean and tighten the positive (+) and negative (-) battery cable connections at the battery, vehicle frame and genset. 2. Recharge or replace the battery. Refer to the battery manufacturer's recommendations. 3. 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) | 1. 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. 2. Clean and tighten the positive (+) and negative (-) battery cable connections at the battery, vehicle frame and genset. 3. Recharge or replace the battery. Refer to the battery manufacturer's recommendations. 4. 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) | 1. Turn on or reset the line circuit breaker on the genset (Page Section 3.10). 2. Turn on or reset the line circuit breakers on the main distribution panel in the vehicle. |
| The genset shuts down abnormally | See Section 11. Troubleshooting |
| 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 |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: (Open or short circuit in fuel injector). See the table for the matching fixes.
Documented causes: (Open or short circuit in MAT sender). See the table for the matching fixes.
Documented causes: (Open or short circuit in MAP sender). See the table for the matching fixes.