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CM870 and ISX Engines – 019-043   Engine Wiring Harness

General Information

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The Signature, ISX engines with EGR use separate wiring harnesses to control the engine and some vehicle operations. There are three connectors for the wiring harnesses. In the picture shown, the following harnesses connect to the ECM from left to right:

  1. ECM power harness
  2. Engine harness
  3. OEM harness.
  
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With EGR


On engines equipped with EGR, there is an EGR valve extension harness. This harness connects to the engine wiring harness and then connects to the EGR valve motor and EGR valve position sensor.

  
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Remove

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Disconnect the harness from the sensors and switches.

  1. Intake manifold pressure sensor
  2. Intake manifold air temperature sensor
  3. Engine and camshaft position sensor
  4. Engine coolant temperature sensor
  5. Fuel shutoff solenoid.

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  1. Engine oil temperature sensor
  2. Engine oil pressure sensor
  3. Wet tank pressure sensor
  4. Water-in-fuel sensor
  5. Turbocharger speed sensor
  6. Rail fuel pressure sensor.

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  1. EGR differential pressure sensor
  2. Exhaust pressure sensor
  3. EGR temperature sensor
  4. EGR valve position sensor
  5. EGR valve motor
  6. Fuel lift pump
  7. Fuel temperature sensor
  8. Timing actuators
  9. Fueling actuators.

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Remove the harness wire ties from the harness support bracket.

Disconnect the engine harnesses from the ECM.

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With EGR


Disconnect the engine wiring harness from the EGR valve extension harness. Disconnect the EGR valve extension harness from the EGR valve motor and the EGR valve position sensor.

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Inspect for Reuse

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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.

  
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With EGR


Inspect the EGR valve extension harness for any cuts, missing insulation on wires, etc. If any defects are found, replace or repair the extension harness.

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Install

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Connect the engine harnesses to the ECM.

Torque Value:  3  n.m  [27 in-lb]

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Connect the harnesses to the sensors and switches.

  1. Intake manifold pressure sensor
  2. Intake manifold air temperature sensor
  3. Engine and camshaft position sensor
  4. Engine coolant temperature sensor
  5. Fuel shutoff solenoid.

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  1. Engine oil temperature sensor
  2. Engine oil pressure sensor
  3. Wet tank pressure sensor
  4. Water-in-fuel sensor
  5. Turbocharger speed sensor
  6. Rail fuel pressure sensor.

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  1. EGR differential pressure sensor
  2. Exhaust pressure sensor
  3. EGR temperature sensor
  4. EGR valve position sensor
  5. EGR valve motor
  6. Fuel lift pump
  7. Fuel temperature sensor
  8. Timing actuators
  9. Fueling actuators.

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

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With EGR


Connect the EGR valve extension harness to the EGR valve motor and the EGR valve position sensor. Connect the EGR valve extension harness to the engine wiring harness.

Start the engine and confirm there are no active faults because the harness was removed and installed.

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Last Modified:  14-Mar-2002
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Published by Jack

Hello, I'm Jack, a diesel engine fan and a blogger. I write about how to fix and improve diesel engines, from cars to trucks to generators. I also review the newest models and innovations in the diesel market. If you are interested in learning more about diesel engines, check out my blog and leave your feedback.