Cummins/Onan MCGCA troubleshooting: 13 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan MCGCA — full specs, parts & maintenance.
All Cummins/Onan fault codes →
| Code | Meaning |
|---|---|
| Low Oil Pressure | Low oil pressure (lower than 14 ±2 PSI) |
| High Engine Temperature | High engine temperature (higher than 220 ±6°F) |
| High Exhaust Temperature | High exhaust temperature (higher than 190 ±9°F) |
| Symptom | Remedy |
|---|---|
| The engine does not crank. | Service the battery and battery terminals and cables. Replace the control circuit fuse if it has blown. |
| The engine cranks, but does not start. | Service the battery and battery terminals and cables. Replace the control circuit fuse if it has blown. |
| The engine coolant temperature gauge indicates 220° F or more while the engine is running. | Shut down the set if possible. Disconnect as many non-critical loads as possible so that the engine will run cooler, and service as soon as possible. |
| The engine shuts down due to high engine temperature or low coolant level. | Shut down the set if possible. Disconnect as many non-critical loads as possible so that the engine will run cooler, and service as soon as possible. |
| The engine oil pressure gauge indicates less than 20 psi. | Fill coolant, if necessary, after the engine has cooled down, and fix any leaks. See Maintenance for servicing the cooling system. |
| The engine shuts down due to low oil pressure or low oil level. | Fill coolant, if necessary, after the engine has cooled down, and fix any leaks. See Maintenance for servicing the cooling system. |
| There is no output because the line circuit breaker (if provided) or the field circuit breaker has tripped. | Reset the tripped fault circuit breaker. |
| Breaker reset button extends out past normal | Push the button to restore operation (after the engine has been properly serviced) |
| The engine coolant temperature gauge indicates 2200F or more while the engine is running. | Shut down the set if possible. See Maintenance for servicing the cooling system. Disconnect as many non-critical loads as possible so that the engine will run cooler, and service as soon as possible. |
| The engine shuts down due to over-speed. | Check the governor-throttle linkage. See Adjustments. Reset the tripped fault circuit breaker. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.