Diagnostic Aids
WARNING: This page is about a different car, the 2007 GMC Sierra, 2007 GMC Cab & Chassis Sierra, 2007 Chevrolet Silverado, and 2007 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Inspect the ECT sensor terminals for corrosion and for engine coolant leaking through the sensor. Engine coolant that is leaking through the sensor will create a high resistance short to ground. This condition results in less voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a warmer ECT.
- This diagnostic runs in a specific range. Measure and record the resistance of the ECT sensor at various ambient temperatures warmer than -8°C (+18°C), then compare those measurements to the Temperature vs Resistance table. Refer to Temperature Versus Resistance (Fuel Temperature Sensor) or Temperature Versus Resistance (EGT Sensors) or Temperature Versus Resistance (IAT Sensor 1) or Temperature Versus Resistance (ECT Sensors) or Temperature Versus Resistance (IAT Sensor 2) .