Sensor Checks
WARNING: This page is about a different car, the 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
- Check for proper operation and performance of the oxygen sensor. Check the oxygen sensor for silicon contamination. Caused by fuel or the use of improper engine sealants, the oxygen sensor will have a white, powdery coating. The sensor will output a high, but false signal voltage. This false rich condition may cause the AF ECM or PCM to reduce the amount of fuel to the engine.
- Check the ECT sensor for proper operation by performing the following:
- Allow the engine temperature to reach ambient air temperature by leaving the engine OFF for several hours, overnight for most accurate results.
- Turn the ignition switch to RUN position, leaving the engine OFF.
- Using a scan tool compare the ECT and IAT sensors displayed temperature. The sensors should be within 5°F (3°C) of each other.
- Replace the ECT sensor or repair the ECT sensor circuit if the ECT is not near the expected value.
- Check for proper MAP sensor operation. A MAP sensor that does not respond quickly and accurately to manifold pressure changes may cause this symptom.