Oxygen Sensor
- Two oxygen sensors are used. A non-heated oxygen sensor is located on exhaust manifold. This oxygen sensor is referred to as the No. 1 or front oxygen sensor. Another heated oxygen sensor is located on exhaust pipe behind catalytic converter. This oxygen sensor is referred to as the No. 2 oxygen sensor or the rear oxygen sensor.
- If problem exists with either oxygen sensor, a diagnostic trouble code will be stored in Engine Control Module (ECM). For diagnostic trouble code diagnosis, see TESTS W/CODES
article.
- To test the heater on No. 2 oxygen sensor, disconnect electrical connector for No. 2 oxygen sensor. Electrical connector for No. 2 oxygen sensor is a Dark Gray 4-pin electrical connector located below passenger's side front seat, behind the carpet, next to side of center console.
- Using ohmmeter, check resistance between terminals +B and HT. See Fig 1. Replace oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C).
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