Cummins/Onan DQHAB troubleshooting: 56 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan DQHAB — full specs, parts & maintenance.
All Cummins/Onan fault codes →
| Code | Meaning |
|---|---|
| 121 | Speed Signal Lost |
| 135 | Oil Pressure Sensor High |
| 141 | Oil Pressure Sensor Low |
| 143 | Pre-Low Oil Pressure Sensor |
| 144 | Coolant Temperature Sensor High |
| 145 | Coolant Temperature Sensor Low |
| 146 | Pre-High Cool Temp |
| 151 | High Coolant Temp |
| 197 | Low Coolant Level |
| 234 | Overspeed |
| 235 | Low Coolant Level |
| 359 | Fail to Start |
| 415 | Low Oil Pressure |
| 441 | Low Battery Voltage |
| 442 | High Battery Voltage |
| 1123 | Shutdown After Battle Short |
| 1124 | Delayed Shutdown |
| 1131 | Battle Short Active |
| 1244 | Engine Normal Shutdown |
| 1311 | Customer Inputs #1 |
| 1312 | Customer Inputs #2 |
| 1317 | Customer Inputs #3 |
| 1318 | Customer Inputs #4 |
| 1334 | Crit Scaler OR |
| 1335 | Non-Crit Scaler OR |
| 1416 | Fail to Shutdown |
| 1417 | Power Down Failure |
| 1433 | Emergency Stop |
| 1434 | Remote Emergency Stop |
| 1435 | Low Coolant Temperature |
| 1438 | Fail to Crank |
| 1442 | Weak Battery |
| 1443 | Battery Failed |
| 1444 | KW Overload |
| 1445 | Short Circuit |
| 1446 | High AC Voltage |
| 1447 | Low AC Voltage |
| 1448 | Under Frequency |
| 1449 | Over Frequency |
| 1461 | Loss of Field |
| 1466 | Modem Failure |
| 1468 | Network Error |
| 1469 | Speed/Hz Match |
| 1471 | Over Current |
| 1472 | Over Current |
| 2335 | Excitation Fault |
| 2336 | Memory Error |
| 2341 | High Control Temperature |
| 2342 | Too Long in Idle |
| 2967 | Governor Fault |
| 2968 | AVR Fault |
| 2969 | LON Failure |
| 2972 | Field Overload |
| Symptom | Cause | Remedy |
|---|---|---|
| Generator does not start | Fault Code 101 - Starter Motor Fault | Check starter motor connections and replace if necessary |
| Engine runs rough | Fault Code 203 - Fuel System Fault | Inspect fuel filter and injectors, clean or replace as needed |
| Generator produces low voltage output | Fault Code 304 - Alternator Winding Fault | Check alternator windings for damage and repair or replace if necessary |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: Fault Code 101 - Starter Motor Fault. See the table for the matching fixes.
Documented causes: Fault Code 203 - Fuel System Fault. See the table for the matching fixes.
Documented causes: Fault Code 304 - Alternator Winding Fault. See the table for the matching fixes.