Cummins/Onan 50.0DDB-9XR troubleshooting: 13 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan 50.0DDB-9XR — full specs, parts & maintenance.
All Cummins/Onan fault codes →
| Symptom | Remedy |
|---|---|
| Fault lamp lights and, engine stops cranking after approximately 75 seconds. | See engine service manual for troubleshooting fuel system, ignition system, etc. After correcting problem, reset the engine monitor by moving run-stop/reset-remote switch to reset position. Release and return to run position. |
| Fault lamp lights immediately after engine starts. | Check for: a. overspeed condition as engine starts. b. high temperature condition. c. faulty high engine temperature sensor or overspeed switch. d. faulty starter disconnect. |
| Fault lamp lights after engine is running. | Check the following: a. Oil level-engine will shut down after approximately 12-172'seconds if low oil pressure sensor does not open. b. Oil pressure sensor may be defective. c. High engine temperature - caused by low coolant level, faulty thermostat, etc. d. Faulty high engine temperature sensor. e. Faulty starter disconnect. |
| Fault lamp lights - no fault condition exists. | Be certain that no fault condition exists. Disconnect lead 29, 30 and 31 from TB11 inside control box (refer to wiring diagram). If fault lamp still lights with leads disconnected, remove and replace engine monitor plug-in printed circuit board. |
| Overcrank fault lamp lights and engine stops cranking after approximately 75 seconds. | See engine service manual for troubleshooting fuel system, ignition system, etc. After correcting fault, reset monitor by moving run-stop/reset-remote switch to reset position, then to either run or remote to restart engine. |
| Overcrank fault lamp lights after engine has run for approximately 75 seconds. | Replace start-disconnect circuit board. |
| High engine temperature lamp lights as soon as engine starts. | Check for defective sensor or actual high temperature condition. |
| Low oil pressure lamp lights after engine is running. | Check: a. Oil level - engine will shut down after approximately 12-1/2 seconds if oil pressure is low. |
| High engine temperature lamp lights after engine is running. | Check for: a. Defective thermostat/thermostats. b. Low coolant level. c. Defective high engine temperature sensor. |
| Overspeed lamp lights - no fault condition exists. | Replace overspeed circuit board. |
| Low oil pressure fault lamp lights r no fault condition exists. | Be certain that no fault condition exists. Disconnect lead 30 from TB11 inside control box (refer to wiring diagram). If low oil pressure lamp still lights, remove and replace engine monitor plug-in printed circuit board. |
| High engine temperature fault lamp lights - no fault condition exists. | Be certain that no fault condition exists. Remove lead 31 from TB11 inside control box (refer to wiring diagram). If high engine temperature lamp still lights, remove and replace engine monitor plug-in printed circuit board. |
| When pressing test lamp button - one or more fault lamps do not light. | Fault lamp/lamps burned out - replace. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.