The Murphy PV405 is a generator-set controller. It is used on generator sets from Generac, including the MAC400FHC and MFH500.
| Symptom | Cause | Remedy |
|---|---|---|
| Clogged air cleaner | Clean or change element. | |
| Clogged intercooler | Contact a GMASD. | |
| Digital Controller Status Messages | Engine coolant temperature < 140 °F (38 °C). Engine rpm < 500 Fuel level < 10% Fuel level < 20%. Fuel level ≤ 16%. Fuel level ≤ 12%. Fuel level ≤ 8%. | Wait approximately 10 seconds after heater powers up. Wait to Start signal Low Fuel Warning • Fuel level notification appears on screen • Low Fuel Level beacon turns on Fuel level ≤ 16% • Fuel level notification appears on screen • Heat/fan load reduced to 50% Fuel level ≤ 12% • Fuel level notification appears on screen • Open heat circuit and close scroll fan circuit • Drop engine to idle Fuel level ≤ 8% • Fuel level notification appears on screen • Engine shuts down |
| Engine control system problem | Contact a GMASD. | |
| Engine cranks but will not start | No fuel. Insufficient oil level. PAS is ON. Air in fuel system. Clogged fuel filter. Gelled fuel. Injection pump failure. Electromagnetic type fuel pump failure. Engine control system failure. | Verify there is no fuel leakage and replenish. Replenish oil to full. Turn PAS to OFF. See Resetting the PAS. Purge air from fuel system. Remove water and change element. Warm fuel pipes with hot water or wait until ambient temperature rises. Contact a GMP ASD. |
| Engine failure | Engine control system failure. | Contact a GMP ASD. |
| Engine has no power | Clogged air cleaner. Clogged pre-fuel filter. Clogged fuel filter. Clogged strainer. | Clean element. Check restriction gauges/replace HTF filters. Remove water and change element. Contact a GMP ASD. |
| Engine overheats | No coolant. Front of radiator is clogged with dust. Subtank cap is not tightened. Fouled coolant. Oil in coolant. Thermostat failure. | Add coolant. See Adding Coolant. Clean with soft brush. Tighten or replace sub tank cap. Clean inside of radiator and change coolant. Contact a GMP ASD. Change thermostat. |
| Engine problem | Contact a GMASD. | |
| Engine running is unstable | Fuel system problem. | |
| Engine starts but stops shortly thereafter | Low idle. | Adjust by idling control equipment on the unit. If adjustment is not possible, contact a GMP ASD. |
| Engine will not crank (electric start) | Discharged battery. Battery terminal is disconnected, loose, or corroded. Starter ground terminal is disconnected, loose, or corroded. Excessive engine oil viscosity. | Replace battery. See Battery Installation and Replacement. Replace corroded part(s) and tighten securely. Examine starter ground terminal and replace if necessary. Change with oil of correct viscosity. See Draining and Refilling the Oil. |
| Exhaust smoke is black | Excessive speed. | Verify engine rpm. Check AVR adjustment. |
| Exhaust smoke is white | Insufficient warm-up time. Engine control system failure. | Conduct warm-up operation. Contact a GMP ASD. |
| Faulty injection pump | Contact a GMASD. | |
| Incorrect fuel type | Electromagnetic type fuel pump problem. | |
| Oil pressure does not rise | Incorrect engine oil viscosity. Insufficient engine oil. | Change with oil of correct viscosity. See Draining and Refilling the Oil. Replenish engine oil. See Draining and Refilling the Oil. |
| Overheat/shutdown condition | (Check controller for engine fault shutdown code) | Access doors are open. Close all access doors. Air outlets are closed. Open the air outlets and verify there are no obstructions or tight bends in the ducting. Front radiator or rear oil cooler are full of debris. Clean the unit. Engine rpm is set too high for ambient temperature. Lower the engine rpm. Faulty temperature sensor. Check air outlet sensor operation. Blower fan operating incorrectly. Remove ducting; check blower fan operation. |
| Water or air in fuel system | Purge air or remove water. See Removing Water From Fuel. |
Fault codes and symptom→remedy steps extracted from this controller’s service/owner documentation; verify against the official manual before servicing. Aggregated from the service documentation of generator sets built on this controller.