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Circuit/System Testing

WARNING: This page is about a different car, the 2010 Saturn Outlook, 2010 GMC Acadia, 2010 Chevrolet Traverse, and 2010 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the ECT sensor.
  2. Ignition OFF, remove the fuse that supplies B+ to circuit terminal X2-56 of the ECM.
    3. CAUTION: Do NOT use a test lamp to test the continuity of the circuit. Damage to the control module may occur due to excessive current draw.
    NOTE: The control module or the sensor may be damaged if the circuit is shorted to battery positive voltage.
  3. Test for less than 5 Ω between the low reference circuit terminal 2 and ground.
    • If greater than specified value, test the circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  4. Install the fuse that supplies B+ to circuit terminal X2-56 of the ECM.
  5. Ignition ON, observe the scan tool the ECT sensor parameter. Verify that the ECT sensor parameter is at -40°C (-40°F).
    • If warmer than the specified value, test the signal circuit for a short to ground. If the circuit/connections test normal, replace the ECM.
    6. NOTE: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the ECT sensor may be damaged.
  6. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool ECT sensor parameter is warmer than 142°C (288°F).
    • If colder than the specified value, test the signal circuit for an open/high resistance or for a short to voltage. If the circuit/connections test normal, replace the ECM.
  7. If all circuits test normal, test or replace the ECT sensor.
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