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Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the ECM.
  2. Connect the J 33431-C  to the engine coolant temperature gage output signal circuit terminal XK67 at the ECM harness connector and ground.
  3. Ignition ON, set the J 33431-C  to generate a speedometer signal. The engine coolant temperature gage should change.
    • If the gage changes, replace the ECM.
    • If the gage does not change, test and repair the signal circuit for the following conditions:
      • An open
      • A short to ground
      • A short to voltage
      • A high resistance
  4. If all circuits test normal, replace the IPC.
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