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. | Verify there is no fuel leakage and replenish. |
| Engine failure | Engine control system failure. | Contact a GMP ASD. |
| Engine has no power | Clogged air cleaner.; Clogged pre-fuel filter.; Clogged fuel filter. | Clean element.; See Removing Water From Fuel.; Remove water and change element. See Removing Water From Fuel. |
| Engine overheats | No coolant.; Front of radiator is clogged with dust.; Sub tank cap is not tightened.; Fouled coolant. | Add coolant. See Adding Coolant.; Clean with soft brush.; Tighten or replace sub tank cap.; Clean inside of radiator and change coolant. See Adding Coolant. |
| 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. | Replace battery. See Battery Installation and Replacement. |
| Exhaust smoke is black | Excessive speed. | Verify engine rpm. Check AVR adjustment. |
| Exhaust smoke is white | Insufficient warm-up time. | Conduct warm-up operation. |
| 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 level. | Change with oil of correct viscosity. See Draining Fluids—Central Fluid Drain System and Refilling Engine Oil.; Replenish oil. See Refilling Engine 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.