Oxygen Sensor
- Two heated oxygen sensors are used. One heated oxygen sensor is on exhaust pipe before front catalytic converter and another heated oxygen sensor is on exhaust pipe behind front 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.
- 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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