Cummins/Onan P4300ie troubleshooting: 9 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan P4300ie — full specs, parts & maintenance.
All Cummins/Onan fault codes →
| Symptom | Cause | Remedy |
|---|---|---|
| When Engine Fails to Start | Check if the DC circuit breaker is turned OFF. Check if the 'O_Lod' (overload) is indicated in the Multi Monitor. Check AC receptacle and DC terminals for loose connection. Check to see if engine starting was attempted with appliances already connected to generator. Depress the circuit breaker into ON position, after making sure the charging current level is proper and the battery is in the normal condition. Stop the engine and check the appliance and/or generator for overloading. Secure connection if necessary. | |
| When No Electricity Is Generated at Receptacle | Check fuel level. Check to make sure generator is not connected to an appliance. Check spark plug for loose spark plug cap. Check spark plug for contamination. Check engine oil level. Check if the recommended spark plug would be adopted. If empty, refill fuel tank making sure not to overfill. If connected, turn off the power switch on the connected appliance and unplug. If loose, push spark plug cap back into place. Remove spark plug and clean electrode. If the engine oil level is low, add the oil to the upper level line on the oil gauge. If not, replace with the recommended spark plug. If the recommended spark plug is not available by all means, make sure to replace with equivalent one of resistance type. | |
| Fails To Crank | Low battery, Bad battery connection, Blown fuse | Check battery fluid level, Clean & tighten all battery & cable connections, Replace fuse on control panel |
| Cranks But Won’t Start | Fuel below generator pickup level in tank, Fuel supply shutoff valve closed, Carbon deposits on spark plug(s), Low oil level | Add fuel, Fully open fuel supply valve, Remove spark plug(s) and replace, Add oil |
| Exhausting Black Smoke | Dirty air filter | Replace air filter |
| Unit Runs Then Stops, Or Stops When Driving Around A Corner | Low fuel level, Low oil level, Excess oil | Add fuel, Add oil, Reduce engine oil level |
| Unit Starts And Runs, Then Stops When The Start Switch Is Released | Low fluid levels, Possible overheating, Other functional problem | Check & bring all fluids up to the appropriate levels, Check for blocked air flow or other possible causes of overheating, Contact an Cummins Onan Authorized RV Service & Parts Dealer |
| Unit Runs Then Surges | Loose or worn spark plug leads, Defective ignition coil, wiring, or control components, Faulty spark plug, Governor out of adjustment, Combustion air pre-heat malfunction, Carburetor icing, Carburetor varnishing | Check spark plug leads at spark plug & ignition coil, Contact an Cummins Onan Authorized RV Service & Parts Dealer, Remove spark plug & clean or replace, Contact an Cummins Onan Authorized RV Service & Parts Dealer, Contact an Cummins Onan Authorized RV Service & Parts Dealer, Contact an Cummins Onan Authorized RV Service & Parts Dealer |
| Circuit Breaker Trips | Overloaded circuit | Turn-off some of the electrical load, and reset the circuit breaker |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: Low battery, Bad battery connection, Blown fuse. See the table for the matching fixes.
Documented causes: Fuel below generator pickup level in tank, Fuel supply shutoff valve closed, Carbon deposits on spark plug(s), Low oil level. See the table for the matching fixes.
Documented causes: Dirty air filter. See the table for the matching fixes.