The Onan (status indicator switch) is a generator-set controller. It is used on generator sets from Cummins/Onan, including the 5.5 HGJAE and 6.5 HGJAE.
Also fitted to: Cummins/Onan 5.5 HGJAD/HGJAE, Cummins/Onan 7.0 HGJAD/HGJAE.
| Code | Meaning | Cause | Remedy |
|---|---|---|---|
| 12 | Overvoltage | ||
| 13 | Undervoltage | ||
| 14 | Overfrequency | ||
| 15 | Underfrequency | ||
| 17 | Fuel Pump Fault | ||
| 19 | Governor Actuator (EFI Only) | ||
| 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.) | |
| 2 | Low Oil Pressure Fault | ||
| 22 | Governor Actuator Overload (EFI Only) | ||
| 23 | Oil Pressure Switch Fault | ||
| 27 | Voltage Sense Lost | ||
| 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. | |
| 3 | Service Check Fault | ||
| 31 | Overspeed Fault (HGJAD, E, F Models Only) | ||
| 32 | Low Cranking Speed Sense | ||
| 33 | Fault Code 33 | ||
| 36 | Genset Stopped Without Fault Condition | ||
| 37 | Invalid Set Configuration | ||
| 38 | Field Overload (Overvoltage) | ||
| 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 | |
| 4 | Overcrank | ||
| 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. 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) | 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. | |
| 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 |
| Code 12 | Over Voltage |
Fault codes and symptom→remedy steps extracted from this controller’s service/owner documentation; verify against the official manual before servicing. Aggregated from the service documentation of generator sets built on this controller.