Highlander & RAV4

WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2002 Toyota Tacoma, 2002 Toyota RAV4, 2002 Toyota Prius, 2002 Toyota MR2, and 2002 Toyota Highlander. However, it is still accessible from the selected car via links, so may be relevant.

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. See Figure and Figure . Replace A/F sensor if resistance is not within specification. See A/F SENSOR HEATER RESISTANCE table. See AIR/FUEL SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.