Tacoma, T100 & 4Runner
- Two heated oxygen sensors are used, one on exhaust pipe in front of catalytic converter, and one on exhaust pipe behind catalytic converter. Heated oxygen sensor on exhaust pipe in front of catalytic converter may be referred to as bank No. 1 sensor No. 1. Heated oxygen sensor exhaust pipe behind catalytic converter may be referred to as bank No. 1 sensor No. 2.
- 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.
- Using ohmmeter, check resistance between +B and HT terminals on electrical connector. See Fig 1. Replace heated oxygen sensor if resistance is not within specification. See OXYGEN SENSOR HEATER RESISTANCE table.
- If problem exists in heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in the Engine Control Module (ECM). For diagnosis of DTC, see appropriate TESTS W/CODES article.
OXYGEN SENSOR HEATER RESISTANCE
| Application | Ohms @ 68°F (20°C) | ||
|---|---|---|---|
| Tacoma | 11-16 | ||
| T100 | |||
| Bank No. 1 Sensor No. 1 | |||
| A/T Models | 11-16 | ||
| M/T Models | 5-7 | ||
| Bank No. 1 Sensor No. 2 | 11-16 | ||
| 4Runner | 11-16 | ||