CM871 and CM876 Electronic Control Systems, ISX and ISM Engines – 019-043   Engine Wiring Harness

The engine uses three separate wiring harnesses to control the engine and some of the vehicle operations. Shown are the electronic control module (ECM) ports for the following connectors:

1. 4-pin OEM power supply harness connector
2. 60-pin Engine harness connector
3. 50-pin OEM harness connector.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

Disconnect the batteries. Refer to Procedure 013-009 in the ISM, ISMe and QSM11 Service Manual, Bulletin 3666322, or the Signature, ISX and QSX15 Service Manual, Bulletin 3666239.

Disconnect the engine harness from the sensors and switches.

• Intake manifold pressure sensor
• Intake manifold air temperature sensor
• Engine and camshaft position sensor
• Engine coolant temperature sensor
• Fuel shutoff solenoid
• Engine oil temperature sensor
• Engine oil pressure sensor
• Wet tank pressure sensor
• Water-in-fuel sensor
• Turbocharger speed sensor
• Rail fuel pressure sensor
• Exhaust gas recirculation (EGR) differential pressure sensor
• Exhaust pressure sensor
• EGR temperature sensor
• EGR valve position sensor
• EGR valve motor
• Fuel lift pump
• Fuel temperature sensor
• Timing actuators
• Fueling actuators
• Aftertreatment fuel pressure sensor
• Aftertreatment fuel injector
• Aftertreatment fuel shutoff valve
• Variable geometry turbocharger (VGT) actuator
• EGR valve
• Crankcase pressure sensor.

Remove the harness wire ties from the harness support bracket.

Disconnect the engine harness connector from the ECM.

Replace or repair the engine harness if there is an open circuit or a short circuit found under the protective covering of the harness body.

Connect the engine harness to the ECM.

Install the harness clamps that hold the engine harness to the block.

Connect the sensors and switches to the engine harness.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

Connect the batteries. Refer to Procedure 013-009 in the ISM, ISMe and QSM11 Service Manual, Bulletin 3666322, or the Signature, ISX and QSX15 Service Manual, Bulletin 3666239.