Cummins/Onan QSF3.8 CM2350 F107 troubleshooting: 10 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan QSF3.8 CM2350 F107 — full specs, parts & maintenance.
All Cummins/Onan fault codes →
| Code | Meaning | Remedy |
|---|---|---|
| 400040 | Wait-to-Start | Wait for the Wait-to-Start lamp to turn off before starting the engine |
| 11000252 | Low Oil Pressure | Shut off the engine immediately to avoid damage |
| Symptom | Cause | Remedy |
|---|---|---|
| Engine Runs Rough at Idle | STEP 4: Allow the engine to warm to operating temperature. If the engine will not reach operating temperature, refer to the Coolant Temperature ig Below Normal troubleshooting symptom tree in Section TS. | |
| Engine Runs Rough or Misfires | STEP 4: Allow the engine to warm to operating temperature. If the engine will not reach operating temperature, refer to the Coolant Temperature ig Below Normal troubleshooting symptom tree in Section TS. | |
| Engine Shuts Off Unexpectedly or Dies During Deceleration | STEP 4: Refer to the Engine Difficult to Start or Will Not Start troubleshooting symptom tree in Section TS. | |
| Moisture in the wiring harness connectors | STEP 5: Dry the connectors with Cummins® electrical contact cleaner, Part Number 3824510. Refer to equipment manufacturer service information. | |
| OEM engine protection system is malfunctioning | STEP 6: Isolate the OEM engine protection system. Follow the OEM service manual instructions to check for a malfunction. | |
| Battery voltage supply to the engine control module (ECM) is low, interrupted, or open | STEP 7: Check the battery connections, the fuses, and the unswitched battery supply circuit. Refer to equipment manufacturer service information. | |
| Air in the fuel system | STEP 8: Check for air in the fuel system. Tighten or replace the fuel connections, fuel lines, fuel tank standpipe, and fuel filters as necessary. | |
| Engine Starts But Will Not Keep Running | Fuel level is low in the tank, Battery voltage supply to the control module (ECM) is low, interrupted, or open, Idle speed is set too low for accessories, Engine-driven units are engaged | Fill the supply tank. Check the battery connections. Adjust the low-idle screw. Disengage engine-driven units. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: STEP 4: Allow the engine to warm to operating temperature. If the engine will not reach operating temperature, refer to the Coolant Temperature ig Below Normal troubleshooting symptom tree in Section TS.. See the table for the matching fixes.
Documented causes: Fuel level is low in the tank, Battery voltage supply to the control module (ECM) is low, interrupted, or open, Idle speed is set too low for accessories, Engine-driven units are engaged. See the table for the matching fixes.