Generac NP-30G troubleshooting: 29 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Generac NP-30G — full specs, parts & maintenance.
| Code | Meaning | Remedy |
|---|---|---|
| QA | W WARNING | |
| M01 | Low Oil Pressure Shutdown | Check the engine oil level. If necessary, add oil to the FULL mark. |
| M02 | High Temperature Shutdown | |
| M03 | Overspeed Shutdown | Do not attempt a manual adjustment to control engine speed. |
| M04 | Low Voltage Shutdown | |
| C1 | Low Oil Pressure Shutdown | Check the engine oil level. |
| T1 | High Temperature Shutdown | |
| S1 | Overspeed Shutdown | Do not attempt a manual adjustment to control the engine speed. |
| V1 | Low Voltage Shutdown | |
| C2 | High Temperature Shutdown | |
| C4 | Low Voltage Shutdown | Disconnect all loads the generator might power by whatever means provided, such as the recreational vehicle’s main circuit breaker. |
| Symptom | Cause | Remedy |
|---|---|---|
| Engine won't crank. | 1. 15 amp fuse is blown 2. Loose, corroded or defective battery cables. 3. Defective engine Start/Stop switch. 4. Defective starter contactor. 5. Defective starter motor. 6. Low or defective battery. | 1. Replace 15 amp fuse. 2. Tighten, clean or replace battery cables as necessary. 3. Replace Start/Stop switch. 4. Replace contactor. 5. Replace starter motor. 6. Change or replace battery. |
| Engine cranks but won't start. | 1. Out of fuel. 2. Fuel pump is defective. 3. Open Wire #14 from Eng. Control Bd. 4. Engine is flooded. 5. Spark plug defective. | 1. Replenish fuel. 2. Replace fuel pump. 3. Reconnect wire. 4. Wait 5-10 min. before trying. 5. Clean, regap or replace plug. |
| Engine starts hard, runs rough, low full load power. | 1. Air cleaner plugged or damaged. 2. Defective spark plug. 3. Loose spark plug boot. | 1. Clean or replace as needed. 2. Clean, regap or replace plug. 3. Press boot on securely. |
| Engine starts, shuts down when Start/Stop switch is released. | 1. Engine oil is low. 2. Engine is overheated. 3. Defective Low Oil Pressure System. 4. Defective Engine Control Board. 5. Defective Computer Contro! Board. | 1. Check oil; add as needed. 2. Check for adequate ventilation. 3. Have serviced/replaced. 4. Have board serviced/replaced. 5. Have board serviced/replaced. |
| Start/Stop switch at Stop, engine continues to run. | 1. Defective Start/Stop switch. | 1. Replace switch. |
| No AC voltage can be measured across Stator connections at the Battery Charge Rectifier (BCR) | An open circuit condition probably exists in Wire 66 (Brown), or Wire 77 (Brown). | Replace Stator Assembly |
| AC voltage is available to the Wire 66 and 77 terminals at the battery Charge Rectifier, but no voltage or a low voltage Is measured between the BCR’s Wire 55 terminal and ground | The Battery Charge Rectifier (BCR) is defective. | |
| Engine starts, but the Stepper Motor does not move, and engine shuts down after several seconds | The CCG circuit board’s micro-controiler may not be operating. | |
| Engine starts, but Stepper Motor does not move. The engine accelerates uncontrollably and shuts down when engine speed exceeds 4500 rpm | A failure of the circuit board’s Stepper Motor drive. | |
| Engine starts, but Stepper Motor does not move. The following symptoms occur: (1) engine appears to operate too slowly. (2) engine is not able to handle the load and unit operates at low AC output voltage. (3) after several seconds under load, AC output voltage is turned off (overload condition) | A failure of the circuit board’s Stepper Motor drive. | |
| Engine can be started, but shuts down after several seconds | A timing detection failure may have occurred (Timing winding, Wires TIM1, TIM2). | |
| Engine speed and output voltage are erratic under constant load, but the AC output does not turn off intermittently | Erratic timing detection may have occurred (Timing winding, Wires TIM1, TIM2). | |
| If the engine starts but the Stepper Motor does not move, and shutdown occurs after several seconds | Broken or shorted Power Supply winding (Wires PS1 and PS2). Broken or shorted Timing winding (Wires TIM1 and TIM2). | |
| If the engine shuts down but speed did NOT exceed 4500 rpm | One of the main windings (Power Phase 1 or 2) is open. One of the main windings (Power Phase 1 or 2) is shorted to ground. | |
| Engine starts, accelerates, shuts down at 4500 rpm | A. Carburetor linkage sticking with throttle stuck open. b. Stepper Motor failed or seized. c. Stepper Motor wire connections broken or disconnected. d. Stepper Motor not properly connected. | A. Repair sticking throttle. b. Replace Stepper Motor. c. Reconnect or repair. d. Reconnect wires. |
| Overvoltage condition and speed control system cannot reduce output voltage | A. Carburetor linkage sticking with throttle stuck partly open. | A. Repair sticking throttle. |
| Stator windings are shorted to ground | The Stator should be cleaned and dried. The Insulation resistance tests should then be repeated. If, after cleaning and drying, the Stator again falls the test, replace the Stator assembly. | |
| A short between windings exists | Clean and dry the Stator. Then, repeat the tests. If Stator falls a second test (after cleaning and drying), replace the Stator assembly. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: 1. 15 amp fuse is blown 2. Loose, corroded or defective battery cables. 3. Defective engine Start/Stop switch. 4. Defective starter contactor. 5. Defective starter motor. 6. Low or defective battery.. See the table for the matching fixes.
Documented causes: 1. Out of fuel. 2. Fuel pump is defective. 3. Open Wire #14 from Eng. Control Bd. 4. Engine is flooded. 5. Spark plug defective.. See the table for the matching fixes.
Documented causes: 1. Air cleaner plugged or damaged. 2. Defective spark plug. 3. Loose spark plug boot.. See the table for the matching fixes.