Cummins/Onan RV QG 2800 RM troubleshooting: 3 fault codes and 58 symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan RV QG 2800 RM — full specs, parts & maintenance.
All Cummins/Onan fault codes →
| Code | Meaning |
|---|---|
| 2 blinks | Low oil pressure fault |
| 3 blinks | Service fault — Press Stop once to cause the two-digit, second-level fault code to blink |
| 4 blinks | Cranking exceeded 30 seconds without the engine starting |
| Symptom | Cause | Remedy |
|---|---|---|
| Fails To Crank | Low battery | Check battery fluid level |
| Fails To Crank | Bad battery connection | Clean & tighten all battery & cable connections |
| Fails To Crank | Blown fuse | Replace fuse on control panel |
| Cranks Slowly | Low battery | Check battery fluid level |
| Cranks Slowly | Bad battery connection | Clean & tighten all battery & cable connections |
| Cranks Slowly | Incorrect oil viscosity | Replace with recommended viscosity oil |
| Cranks Slowly | Load connected | Disconnect load before starting |
| Cranks But Won't Start | Fuel below generator pickup level in tank | Add fuel |
| Cranks But Won't Start | Fuel supply shutoff valve closed | Fully open fuel supply valve |
| Cranks But Won't Start | Carbon deposits on spark plug(s) | Remove spark plug(s) and replace |
| Cranks But Won't Start | Low oil level | Add oil |
| Exhausting Black Smoke | Dirty air filter | Replace air filter |
| Exhausting Black Smoke | Choke stuck or misadjusted | Contact an Cummins Onan Authorized RV Service & Parts Dealer |
| Unit Runs Then Stops, Or Stops When Driving Around A Corner | Low fuel level | Add fuel |
| Unit Runs Then Stops, Or Stops When Driving Around A Corner | Low oil level | Add oil |
| Unit Runs Then Stops, Or Stops When Driving Around A Corner | Excess oil | Reduce engine oil level |
| Unit Starts And Runs, Then Stops When The Start Switch Is Released | Low fluid levels | Check & bring all fluids up to the appropriate levels |
| Unit Starts And Runs, Then Stops When The Start Switch Is Released | Possible overheating | Check for blocked air flow or other possible causes of overheating |
| Unit Starts And Runs, Then Stops When The Start Switch Is Released | Other functional problem | Contact an Cummins Onan Authorized RV Service & Parts Dealer |
| Unit Starts And Runs, Then Stops When The Start Switch Is Released | No AC output | Contact an Cummins Onan Authorized RV Service & Parts Dealer |
| Unit Runs Then Surges | Loose or worn spark plug leads | Check spark plug leads at spark plug & ignition coil |
| Unit Runs Then Surges | Defective ignition coil, wiring, or control components | Contact an Cummins Onan Authorized RV Service & Parts Dealer |
| Unit Runs Then Surges | Faulty spark plug | Remove spark plug & clean or replace |
| Unit Runs Then Surges | Governor out of adjustment | Contact an Cummins Onan Authorized RV Service & Parts Dealer |
| Unit Runs Then Surges | Combustion air pre-heat malfunction | Contact an Cummins Onan Authorized RV Service & Parts Dealer |
| Unit Runs Then Surges | Carburetor icing | Move carburetor pre-heater to the winter position |
| Unit Runs Then Surges | Carburetor varnishing | Try fuel system cleaner and contact dealer if no change |
| Circuit Breaker Trips | Overloaded circuit | Turn-off some of the electrical load, and reset the circuit breaker |
| No Electric Output | Tripped circuit breaker | Reset the circuit breaker |
| No Electric Output | Other function problem | Contact a Cummins Onan Authorized RV Service & Parts Dealer |
| Fails To Crank | Low battery. | Check battery fluid level. |
| Fails To Crank | Bad battery connection. | Clean & tighten all battery & cable connections. |
| Fails To Crank | Blown fuse. | Replace fuse on control panel. |
| Cranks Slowly | Low battery. | Check battery fluid level. |
| Cranks Slowly | Bad battery connection. | Clean & tighten all battery & cable connections. |
| Cranks Slowly | Incorrect oil viscosity. | Replace with recommended viscosity oil. |
| Cranks Slowly | Load connected. | Disconnect load before starting. |
| Cranks But Won’t Start | Fuel below generator pickup level in tank. | Add fuel. |
| Cranks But Won’t Start | Fuel supply shutoff valve closed. | Fully open fuel supply valve. |
| Cranks But Won’t Start | Carbon deposits on spark plug(s). | Remove spark plug(s) and replace. |
| Cranks But Won’t Start | Low oil level. | Add oil. |
| Exhausting Black Smoke | Dirty air filter. | Replace air filter. |
| Exhausting Black Smoke | Choke stuck or misadjusted. | Contact an Cummins Onan Authorized RV Service & Parts Dealer. |
| Unit Runs Then Stops, Or Stops When Driving Around A Corner | Low fuel level. | Add fuel. |
| Unit Runs Then Stops, Or Stops When Driving Around A Corner | Low oil level. | Add oil. |
| Unit Runs Then Stops, Or Stops When Driving Around A Corner | Excess oil. | Reduce engine oil level. |
| Unit Starts And Runs, Then Stops When The Start Switch Is Released | Low fluid levels. | Check & bring all fluids up to the appropriate levels. |
| Unit Starts And Runs, Then Stops When The Start Switch Is Released | Possible overheating. | Check for blocked air flow or other possible causes of overheating. |
| Unit Starts And Runs, Then Stops When The Start Switch Is Released | Other functional problem. | Contact an Cummins Onan Authorized RV Service & Parts Dealer. |
| Unit Starts And Runs, Then Stops When The Start Switch Is Released | No AC output. | Contact an Cummins Onan Authorized RV Service & Parts Dealer. |
| Unit Runs Then Surges | Loose or worn spark plug leads. | Check spark plug leads at spark plug & ignition coil. |
| Unit Runs Then Surges | Defective ignition coil, wiring, or control components. | Contact an Cummins Onan Authorized RV Service & Parts Dealer. |
| Unit Runs Then Surges | Faulty spark plug. | Remove spark plug & clean or replace. |
| Unit Runs Then Surges | Governor out of adjustment. | Contact an Cummins Onan Authorized RV Service & Parts Dealer. |
| Unit Runs Then Surges | Combustion air pre-heat malfunction. | Contact an Cummins Onan Authorized RV Service & Parts Dealer. |
| Unit Runs Then Surges | Carburetor icing. | Move carburetor pre-heater to the winter position. |
| Unit Runs Then Surges | Carburetor varnishing. | Try fuel system cleaner and contact dealer if no change. |
| 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: Loose or worn spark plug leads; Defective ignition coil, wiring, or control components; Faulty spark plug; Governor out of adjustment. See the table for the matching fixes.
Documented causes: Low battery; Bad battery connection; Incorrect oil viscosity; Load connected. See the table for the matching fixes.
Documented causes: Low fluid levels; Possible overheating; Other functional problem; No AC output. See the table for the matching fixes.