Land Cruiser, Sequoia, Tundra 4.7L & 4Runner 4.7L
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2003 Toyota Tundra, 2003 Toyota Tacoma, 2003 Toyota Sienna, 2003 Toyota Sequoia, and 2003 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
- Four heated oxygen sensors are used, one on each exhaust manifold and one on each exhaust pipe behind catalytic converter. On driver's side, heated oxygen sensor on exhaust manifold may also be referred to as bank No. 1 sensor No. 1 and heated oxygen sensor on exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2. On passenger's side, heated oxygen sensor on exhaust manifold may also be referred to as bank No. 2 sensor No. 1 and heated oxygen sensor on exhaust pipe behind catalytic converter may also be referred to as bank No. 2 sensor No. 2.
- To test heater on heated oxygen sensor, disconnect electrical connector at 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. On Land Cruiser, Sequoia and 4Runner 4.7L, resistance should be 11-16 ohms at 68°F (20°C). On Tundra 4.7L, resistance should be 11-16 ohms at 68°F (20°C) and 23-32 ohms at 1472°F (800°C). On all models, replace heated oxygen sensor if resistance is not within specification. See HEATED OXYGEN SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
- On 4Runner 4.7L, to check that heater is not shorted, using ohmmeter, check that no continuity exists between E1 and HT terminals on electrical connector. See Figure. Replace heated oxygen sensor if continuity exists. See HEATED OXYGEN SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
- On all models, if a problem exists in heated oxygen 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.