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Testing the Control Module Circuits

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  1. Ignition OFF, disconnect the harness connectors at an easily accessible control module that is not communicating.
  2. Ignition OFF and all vehicle systems OFF, all key fobs at least 3 meters away from vehicle, all access doors closed. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 10 Ω between each ground circuit terminal and ground, at the control module connector that was just disconnected.
    • If greater than the specified range, test the ground circuit and ground connection for an open/high resistance.
  3. Ignition OFF, verify that a test lamp does not illuminate between each ignition circuit terminal and ground.
    • If the test lamp does illuminate, test the ignition circuit for a short to voltage. If the circuits test normal, replace the appropriate control module.
  4. Ignition ON, verify that a test lamp illuminates between each ignition circuit terminal and ground.
    • If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the appropriate control module.
  5. Ignition OFF, connect the harness connectors at the control module that was disconnected.
  6. Repeat step 1 at another control module that is not communicating until one of the following conditions are isolated:
    • An open/high resistance on the ground circuit or ground connection
    • A short to voltage, a short to ground, or an open/high resistance on the ignition circuit
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