Highlander & RAV4
- Two heated A/F sensors are used. Heated A/F sensors are mounted on exhaust manifold above catalytic converters. A/F sensor for cylinders No. 1 and 4 is referred to as bank No. 1 sensor No. 1. A/F sensor for cylinders No. 2 and 3 is referred to as bank No. 2 sensor No. 1. If problem exists in A/F sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.
- To test heater resistance on A/F sensor, disconnect electrical connector for A/F sensor. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 561)and (Scheme 562). Replace A/F sensor if resistance is not within specification. See «A/F SENSOR HEATER RESISTANCE (HIGHLANDER & RAV4)»(ref-151978-S11551952372003091800000) table. See «AIR/FUEL SENSOR»(ref-151983-S13377169182003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
| Application & Temperature | Ohms | |
|---|---|---|
| Highlander | ||
| 68°F (20°C) | 1.8-3.4 | |
| 932°F (500°C) | 5.0-7.5 | |
| RAV4 | ||
| 68°F (20°C) | .8-1.4 | |
| 1472°F (800°C) | 1.8-3.2 | |
A/F SENSOR HEATER RESISTANCE (HIGHLANDER & RAV4)
Scheme 561
Scheme 562
Scheme 563
- Heated A/F sensor is mounted on exhaust pipe in front of catalytic converter. If problem exists in A/F sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See «SELF-DIAGNOSTIC SYSTEM»(ref-151974-S27066196352003010900000) in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.
- To test heater resistance on A/F sensor, disconnect electrical connector for A/F sensor. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 563) Replace A/F sensor if resistance is not within specification. See «A/F SENSOR HEATER RESISTANCE (TACOMA)»(ref-151978-S32376423982003010900000) table. See «AIR/FUEL SENSOR»(ref-151983-S13377169182003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article. A/F SENSOR HEATER RESISTANCE (TACOMA) Application & Temperature Ohms 68°F (20°C).8-1.4 1472°F (800°C) 1.8-3.2