Oxygen Sensor
- Two heated oxygen sensors are used. One heated oxygen sensor is on exhaust manifold before catalytic converter and another heated oxygen sensor is on exhaust pipe behind catalytic converter.
- If problem exists with heated 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 heated oxygen sensor, disconnect electrical connector from appropriate heated oxygen sensor and note heated oxygen sensor terminals. See Figure.
- Electrical connector for heated oxygen sensor on exhaust pipe behind catalytic converter is a Dark Gray 4-pin electrical connector located below passenger's side front seat, below the carpet, near center console.
- Using ohmmeter, check resistance between heated oxygen sensor terminals +B and HT. See Figure. Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C).
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