Skip to content

Telegram : @Diezel365

Cummins ISX CM870 (2003-06) Fault Code: 187 PID: S232 SPN: 1080 FMI: 4/4 Sensor Supply 2 Circuit – Voltage Below Normal or Shorted to Low Source. Low voltage detected at the sensor supply number 2 circuit.

Low voltage on the +5 volt supply line can be caused by a short circuit to ground in a supply line, a short circuit between a supply line and a return line, a malfunctioning sensor, or a malfunctioning ECM power supply.

During the fault code response test outlined for each sensor connected to sensor supply number 2, Fault Code 187 must be active before unplugging each sensor. If the fault code is not active, but can be easily duplicated by operating the engine, the following can be performed:

Operate the engine under the conditions that will cause Fault Code 187 to become active, even if it logs for a short period of time. Unplug one sensor at a time until Fault Code 187 stops logging under the test conditions. Each sensor can be unplugged with the engine running. Note: The engine may not start if the camshaft position sensor is unplugged.

Possible repair:

1)Replace the camshaft position sensor.2)Replace the intake manifold pressure/temperature sensor.3)Replace the EGR valve position sensor.4)Replace the EGR differential pressure sensor.5)Replace the rail fuel pressure sensor.6)Replace the exhaust gas pressure sensor.7)Repair or replace the engine harness.8)Replace ECM.

Cummins ISX CM870 (2003-06) Fault Code: 155 PID: P105 SPN: 105 FMI: 0/0 Intake Manifold 1 Temperature – Data Valid But Above Normal Operating Range – Most Severe Level. Intake manifold air temperature signal indicates intake manifold air temperature above engine protection critical limit.
Cummins ISX CM870 (2003-06) Fault Code: 154 PID: P105 SPN: 105 FMI: 4/4 Intake Manifold 1 Temperature Sensor Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at intake manifold air temperature circuit.
Cummins ISX CM870 (2003-06) Fault Code: 153 PID: P105 SPN: 105 FMI: 3/3 Intake Manifold 1 Temperature Sensor Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage detected at intake manifold air temperature circuit.
Cummins ISX CM870 (2003-06) Fault Code: 151 PID: P110 SPN: 110 FMI: 0/0 Engine Coolant Temperature – Data Valid But Above Normal Operating Range – Most Severe Level. Engine coolant temperature signal indicates engine coolant temperature above engine protection critical limit.
Cummins ISX CM870 (2003-06) Fault Code: 145 PID: P110 SPN: 110 FMI: 4/4 Engine Coolant Temperature 1 Sensor Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at engine coolant temperature circuit.
Cummins ISX CM870 (2003-06) Fault Code: 144 PID: P110 SPN: 110 FMI: 3/3 Engine Coolant Temperature 1 Sensor Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage or open circuit detected at engine coolant temperature circuit