The L401 is a generator-set controller. It is used on generator sets from Isuzu and Magnum, including the 4LE2TAGV-03 and MLT4200IF4.
Used across brands: Isuzu, Magnum
| Code | Meaning | Remedy |
|---|---|---|
| 0 | In case of an emergency, always press the emergency stop switch located on the side of the unit to stop the engine immediately. The Stop/Reset (O) button may delay the engine shutdown if stop faults exist. | To prevent damage to the generator and connected equipment, remove all loads from the generator by opening all circuit breakers (turn to the OFF (O) position) before pressing the Stop/Reset (O) button. |
| Symptom | Cause | Remedy |
|---|---|---|
| HIGH COOLANT TEMPERATURE SHUTDOWN | Engine will shut down when coolant temperature is 210°F (99°C) or more. | Check the coolant level in the overflow jug. Restart the engine and read the coolant temperature to verify a high coolant temperature shutdown. Stop the engine immediately if the coolant temperature is 210°F (99°C) or more. Allow the engine to cool. Add coolant to the overflow jug if it is low and then check the level of coolant in the radiator. Check the radiator shroud and ducting for blockage and remove any foreign matter. Inspect coolant hoses, engine block and water pump for visible leaks. Check the tension of the serpentine drive belt for the water pump. If no other problems are found, remove the load on the generator and restart the engine. |
| LOW OIL PRESSURE SHUTDOWN | Engine controller will shut the engine down when the oil pressure is less than 15 psi (103 kPa). | Check the level of the engine oil with the dipstick. Add oil if required. Visually inspect the engine for oil leaks. |
| Mast lights on but the light output is low | Fixture and/or lens is dirty. Clean reflective surface inside fixture and both inside and outside surfaces of lenses. | |
| Ured current has fallen below the configured trip level | This is used to detect lamp failure. |
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.