Oxygen Sensor
- Two heated oxygen sensors are used. One heated oxygen sensor is on exhaust pipe before front catalytic converter. This oxygen sensor is referred to as the No. 1 or front oxygen sensor. Another heated oxygen sensor is located on exhaust pipe behind front catalytic converter. This oxygen sensor is referred to as the No. 2 oxygen sensor or the rear oxygen sensor.
- If problem exists 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 the oxygen sensor, disconnect electrical connector from appropriate oxygen sensor. Using ohmmeter, check resistance between terminals +B and HT. See Fig 1 and Fig 2. Replace oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C).
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002