Circuit/System Testing
- Allow the engine to cool to ambient air temperature.
- Ignition ON, observe the scan tool ECT sensor parameter and the scan tool intake air temperature (IAT) sensor parameter. The ECT and the IAT readings should be within 2 or 3 degrees of each other.
- If not within the specified range, test the ECT sensor. If the ECT sensor tests normal, test for high resistance in the ECT sensor signal circuit terminal 2 and the ECT sensor low reference circuit terminal 1. If the circuits test normal, replace the PCM.
- Start the engine, immediately observe the scan tool ECT sensor parameter. Observe the ECT sensor reading for 10 minutes. The ECT reading should increase by greater than 20°C (36°F).
- If less than the specified range, test for the following conditions:
- If you find any of the above conditions, repair as necessary.