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Testing the Control Module Circuits

  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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