Cummins/Onan DFGB troubleshooting: 12 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan DFGB — full specs, parts & maintenance.
All Cummins/Onan fault codes →
| Code | Meaning | Cause | Remedy |
|---|---|---|---|
| 1131 | Battle Short Active. | This feature must only be used during supervised, temporary operation of the genset. The faults that are overridden during Battle Short mode consist of faults that can affect genset performance or cause permanent engine, alternator, or connected equipment damage. | |
| 1416 | Fail To Shut Down is displayed. | The Fault Acknowledgement/Reset button will clear the fault message, but will remain in the Fault/History file with an asterisk sign (* equals active fault) as long as Battle Short mode is enabled. | |
| 1123 | Shutdown After Battle Short will be displayed for this type of shutdown. | Battle Short is suspended and a shutdown occurs immediately if any of the following critical shutdown faults occur: Overspeed − Fault code 234, Emergency Stop − Fault code 1433, Remote Emergency Stop − Fault code 1434, Speed Signal Lost − Fault code 121, Excitation Fault − Fault code 2335. Moving the customer installed Battle Short switch to OFF with an active but overridden shutdown fault or a shutdown fault that was overridden at any time. | |
| 401 | The generator set does not start. | Possible causes include: low fuel level, faulty starter motor, or a malfunctioning ignition system. | Check the fuel level and refill if necessary. Test the starter motor for functionality. Inspect the ignition system for any issues. |
| 402 | The generator set produces low voltage output. | Possible causes include: dirty or clogged air filter, malfunctioning alternator, or a faulty voltage regulator. | Clean the air filter and check for any blockages. Inspect the alternator for signs of damage or wear. Test the voltage regulator to ensure it is functioning correctly. |
| 403 | The generator set produces high temperature warnings. | Possible causes include: insufficient coolant, malfunctioning thermostat, or a clogged radiator. | Check the coolant level and top up if necessary. Inspect the thermostat for any signs of failure. Clean the radiator to ensure proper airflow. |
| Symptom | Cause | Remedy |
|---|---|---|
| Make sure the fuel tanks have sufficient fuel and that fuel system is primed. | Check to make sure there are no leaks and that all fittings are tight. | |
| Make sure the generator set cooling inlet/outlet and exhaust ventilation openings are clear (not blocked) and operational. | Remove all loose debris from surrounding area of generator set. Air flow from the radiator fan can blow loose items around and into ventilation openings. | |
| Status Indicators are not functioning properly. | Check the status indicators for any visible damage or loose connections. If the issue persists, refer to the troubleshooting table. | |
| Control and diagnostics via network or PC (laptop) are not working. | Ensure that the network connection is stable and correct. Check the control panel settings for any misconfigurations. Refer to the troubleshooting table if issues continue. | |
| The generator set produces excessive noise during operation. | Possible causes include: loose or damaged engine components, worn-out bearings, or a malfunctioning muffler. | Inspect the engine for any loose parts and tighten as necessary. Check the bearings for wear and replace if needed. Test the muffler to ensure it is functioning properly. |
| Fail to Start Indicator: This red lamp indicates the engine failed to start. | To clear a Fail to Start shutdown, place the O/Manual/Auto switch in the O position and press the Fault Acknowledge/Reset button. Before attempting to restart, wait two minutes for the starter motor to cool and then repeat the starting procedure. If the engine does not run after a second attempt, refer to the Troubleshooting section. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: This feature must only be used during supervised, temporary operation of the genset. The faults that are overridden during Battle Short mode consist of faults that can affect genset performance or cause permanent engine, alternator, or connected equipment damage.. See the table for the matching fixes.
Documented causes: Possible causes include: low fuel level, faulty starter motor, or a malfunctioning ignition system.. See the table for the matching fixes.
Documented causes: Possible causes include: dirty or clogged air filter, malfunctioning alternator, or a faulty voltage regulator.. See the table for the matching fixes.