LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Cadillac >> 2006 >> STS V >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 4.4L - DTC P0010 To P0175 >> DTC P0128 >> Circuit/System Testing
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Circuit/System Testing

IMPORTANT: All electrical components and accessories must be turned OFF and allowed to power down.
  1. Ignition OFF, disconnect the ECT harness connector at the ECT sensor.
  2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal Band 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.
  3. Ignition ON, verify the scan tool ECT Sensor parameter is less than -39°C (-38°F).
    • If greater than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the ECM.
  4. Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B Verify the scan tool ECT Sensor parameter is greater than 149°C (300°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.
  5. If all circuits test normal, test or replace the ECT sensor.
scientia non olet · About LEMON Manuals