Cummins/Onan 350 IDIFIN troubleshooting: 20 symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan 350 IDIFIN — full specs, parts & maintenance.
All Cummins/Onan fault codes →
| Symptom | Cause | Remedy |
|---|---|---|
| Engine stops cranking and fault lamp lights, after cranking approximately 75 seconds | Check for empty fuel tank, fuel system leaks, or plugged fuel filters and/or supply lines. Correct as required. | |
| Fault lamp lights immediately after engine starts and unit shuts down | Possible overspeed condition | Check the governor and throttle linkage for binding and freedom of movement. Check electronic governor connections. Contact an Onan Distributor or the engine manufacturer if linkage is not at fault. |
| Fault lamp lights and engine shuts down after running for a period | Low oil level | Check oil level and replenish if necessary. |
| Fault lamp lights and engine shuts down after running for a period | Low coolant level | Check coolant level of radiator and heat exchanger sets and replenish if necessary. |
| Fault lamp lights and engine shuts down after running for a period | Slipping drive belts or obstructions to the airflow | Check for slipping drive belts or for obstructions to the airflow. |
| Fault lamp lights and engine shuts down after running for a period | Water flow valve on city water cooled sets out of adjustment | Check water flow valve on city water cooled sets and adjust if necessary. |
| Fault lamp lights and engine shuts down after running for a period | None of the above | Contact an Onan Distributor or the engine manufacturer if none of the above. |
| Engine runs, shuts down and cranks for 75-seconds. Cranking cycle stops; fault lamp lights | Dirty fuel filters | Check for dirty fuel filters and replace if necessary. (See MAINTENANCE section) |
| Engine runs, shuts down and cranks for 75-seconds. Cranking cycle stops; fault lamp lights | Dirty or plugged air filters | Check for dirty or plugged air filters and replace if necessary. (See MAINTENANCE section) |
| Fault lamp lights, no fault exists | Engine monitor board or sensor malfunction | Contact an Onan Distributor. |
| Overcrank fault lamp lights and engine stops cranking after approximately 75-seconds | Check for empty fuel tank, fuel system leaks, or plugged fuel filters, and/or supply lines. Correct as required. | |
| Engine runs, shuts down, cranks for 75-seconds, cranking cycle stops, overcrank light ON | Dirty fuel filters | Check for dirty fuel filters and replace if necessary. (See MAINTENANCE section). |
| Engine runs, shuts down, cranks for 75-seconds, cranking cycle stops, overcrank light ON | Dirty or plugged air filters | Check for dirty or plugged air filters and replace if necessary. (See MAINTENANCE section) |
| Low oil pressure shutdown | Low oil level | Check oil level and replenish if necessary. Contact an Onan Distributor if oil level is correct. |
| High engine temperature shutdown | Low coolant level | Check coolant level of radiator and heat exchanger sets and replenish if necessary. |
| High engine temperature shutdown | Slipping drive belts or obstructions to the airflow | Check for slipping drive belts or for obstructions to the airflow. |
| High engine temperature shutdown | Water flow valve on city water cooled sets out of adjustment | Check water flow valve on city water cooled sets and adjust if necessary. |
| High engine temperature shutdown | None of the above | Contact an Onan Distributor or the engine manufacturer if none of the above. |
| Overspeed shutdown | Governor and throttle linkage binding or restricted movement; electronic governor wire connections | Check the governor and throttle linkage for binding and freedom of movement. Check wire connections on electronic governor. Contact an Onan Distributor or the engine manufacturer if linkage is not at fault. |
| Overspeed light on, no shutdown. Low oil pressure light ON. No shutdown. High engine temperature light ON. No shutdown | Engine monitor board or sensor malfunction | Contact an Onan Distributor. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: Low oil level; Low coolant level; Slipping drive belts or obstructions to the airflow; Water flow valve on city water cooled sets out of adjustment. See the table for the matching fixes.
Documented causes: Low coolant level; Slipping drive belts or obstructions to the airflow; Water flow valve on city water cooled sets out of adjustment; None of the above. See the table for the matching fixes.
Documented causes: Dirty fuel filters; Dirty or plugged air filters. See the table for the matching fixes.