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Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the glow plug control module.
  2. Ignition ON, test for greater than 10 volts between the glow plug control module control circuit terminal 10 and ground.
    • If less than the specified range, test the control circuit for an open or a short to ground. If the circuit tests normal, replace the ECM.
  3. Test the A/C frequency from the glow plug control module control circuit terminal 10. Command the glow plug control module ON with a scan tool. Verify the A/C frequency is between 30-35 Hz.
    • If less than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
    • If greater than the specified range, test the control circuit for a high resistance. If the circuit tests normal, replace the ECM.
  4. If the circuit tests normal, test or replace the glow plug control module.
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