Cummins ISB CM550 (1990-94) Fault Code: 365 PID: SID 233 SPN: 1077 FMI: 4 Fuel Pump Voltage Out of Range Error Low

Circuit Description
Power is supplied to the through a relay. When the engine control module (ECM) switches the relay, power is supplied from the battery, through the relay, to the fuel pump.

Component Location
Internal to the pump.

Shop Talk
The fuel pump control module compares battery voltage to supply voltage while energizing the fuel metering solenoid. If this measured voltage drop is excessive, there is high resistance in the fuel pump power supply circuit.