Heated Oxygen Sensor
- Three heated oxygen sensors are used. A heated oxygen sensor is used on each exhaust manifold. Heated oxygen sensor on front (radiator side) exhaust manifold may be referred to as bank No. 2 sensor No. 1. Heated oxygen sensor on rear (firewall side) exhaust manifold may be referred to as the bank No. 1 sensor No. 1. Another heated oxygen sensor is used on exhaust pipe behind catalytic converter. This heated oxygen sensor may be referred to as the bank No. 1 sensor No. 2.
- If problem exists with any one of the 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 the heated oxygen sensor, disconnect electrical connector from appropriate heated oxygen sensor and note heated oxygen sensor terminals. See Fig 1.NOTE: Electrical connector for heated oxygen sensor on exhaust pipe behind catalytic converter is located below passenger's side front seat, near center console on column shift models and contains a Dark Gray 4-pin electrical connector. On floor shift models, electrical connector is located on passenger's side, below carpet, near center console and contains a Dark Gray 4-pin electrical connector.
- On all heated oxygen sensors, use ohmmeter to check resistance between heated oxygen sensor terminals +B and HT. See Fig 1. Replace heated oxygen sensor if resistance is not within specification. See OXYGEN SENSOR HEATER RESISTANCE table.
OXYGEN SENSOR HEATER RESISTANCE
| Application | Ohms @ 68°F (20°C) |
|---|---|
| Avalon | 11-16 |