Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Chevrolet >> 2006 >> Epica LT >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 2.5L (LBK) - DTC P0030 To DTC P0230 >> DTC P0125 or P0128 >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector of the ECT sensor.
  2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit and ground.
    • If greater than 5 ohms, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Ignition ON, using a scan tool verify that the ECT sensor parameter is at -40°C (-40°F).
    • If greater than -40°C (-40°F), test the signal circuit of the ECT sensor for a short to ground. If the circuit/connections test normal, replace the ECM.
    4. IMPORTANT: If the signal circuit of the ECT sensor is shorted to voltage the ECT sensor may be damaged.
  4. Install a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the ECT sensor. Verify the ECT sensor parameter is greater than 128°C (262°F).
    • If less than 128°C (262°F), test the signal circuit of the ECT sensor for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM.
  5. If all circuit/connections test normal, test or replace the ECT sensor.
scientia non olet · About Mike's Workshop Manuals