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Home >> Buick >> 2007 >> Allure CX >> Repair and Diagnosis >> External Pages >> Different car >> Section 64 (Engine Control System & Fuel System - 3.6L - DTC P0008 To DTC P0333) >> DTC P0125 or P0128 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the engine coolant temperature (ECT) sensor.
  2. Remove the fuse that supplies B+ to circuit terminal X2-36 of the engine control module (ECM).
  3. Test for less than 5 ohms between the low reference circuit terminal 2 and ground.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  4. Install the fuse that supplies B+ to circuit terminal X2-36 of the ECM.
  5. Ignition ON, verify the scan tool ECT sensor parameter is at -40°C (-40°F).
    • If greater than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
    6. IMPORTANT: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.
  6. Ignition ON, connect a 3A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool ECT sensor parameter is greater than 142°C (288°F).
    • If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  7. If all circuits test normal, test or replace the ECT sensor.
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