Heated Oxygen Sensor
- Two heated oxygen sensors are used. A heated oxygen sensor is used on exhaust pipe in front of front catalytic converter. This oxygen sensor is referred to as the No. 1 oxygen sensor or front oxygen sensor. Another heated oxygen sensor is located on exhaust pipe behind rear catalytic converter. This oxygen sensor is referred to as the No. 2 oxygen sensor or the rear oxygen sensor.
- If a problem exists with No. 1 or 2 heated oxygen sensors, 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 the No. 1 or 2 oxygen sensors, disconnect electrical connector for appropriate heated oxygen sensor. See Fig 1. Note terminals on heated oxygen sensor. See Fig 1.
- Using ohmmeter, check resistance between heated oxygen sensor terminals +B and HT. See Fig 1. Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C).
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