Cummins ISB CM850 (2003-06) Fault Code: 284 PID: SID 221 SPN: 1043 FMI: 4 Engine Speed/Position Sensor (Crankshaft) Supply Voltage Circuit – Voltage Below Normal or Shorted to Low Source. Low voltage detected on the ECM voltage supply line to engine speed sensor.
Low voltage on the +5 VDC supply line can be caused by a short circuit to ground in a supply line, a short circuit between a supply line or a return line, a failed sensor, or a failed ECM power supply.
Possible repairs:
1)Replace the engine speed sensor.
2)Replace the engine harness.
3)Replace the ECM.
Cummins ISB CM850 (2003-06) Fault Code: 281 PID: SID 126 SPN: 1347 FMI: 7 Fuel Pump Pressurizing Assembly 1 – Mechanical System Not Responding Properly or Out of Adjustment. A pumping imbalance between the front and rear pumping plungers has been detected.
Cummins ISB CM850 (2003-06) Fault Code: 275 PID: SID 126 SPN: 1347 FMI: 7 Fuel Pumping Element Number 1 (Front) – Mechanical System Not Responding Properly or Out of Adjustment.
Cummins ISB CM850 (2003-06) Fault Code: 272 (ISC – Auto) PID: SID 126 SPN: 1347 FMI: 3 High Fuel Pressure Solenoid Valve Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage or open circuit detected at the fuel pump actuator circuit.
Cummins ISB CM850 (2003-06) Fault Code: 272 (Auto) PID: SID 126 SPN: 1347 FMI: 3 High Fuel Pressure Solenoid Valve Circuit – Voltage Above Normal or Shorted to High Source. Electronic fuel control actuator shorted high.
Cummins ISB CM850 (2003-06) Fault Code: 271 (ISC – Auto) PID: SID 126 SPN: 1347 FMI: 4 High Fuel Pressure Solenoid Valve Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the fuel pump actuator circuit.
Cummins ISB CM850 (2003-06) Fault Code: 271 (Auto) PID: SID 126 SPN: 1347 FMI: 4 High Fuel Pressure Solenoid Valve Circuit – Voltage Below Normal or Shorted to Low Source. Electronic fuel control actuator shorted low.
