Diagnosis & Repair
- Connect scan tool to Data Link Connector (DLC) No. 3. See Figure. Start engine and warm to normal operating temperature. Using scan tool, monitor bank No. 1, sensor No. 1 and bank No. 2, sensor No. 1. Snap accelerate engine 3 times. Sensors should indicate a rich signal (.45 volt or more) at least once.
- If a rich signal is indicated for both sensors, replace ECM and retest. If either sensor does not display a rich signal, check for open or short circuit in wiring harness between ECM and suspect sensor. Repair as necessary. If wiring harness is are okay, replace oxygen sensor and retest.