Diagnosis & Repair
WARNING: This page is about a different car, the 2002 Toyota Highlander. However, it is still accessible from the selected car via links, so may be relevant.
- Access ECM behind glove box. See Figure. Turn ignition on. Using DVOM, backprobe appropriate ECM harness connector. For heated oxygen sensor bank No. 1 sensor No. 2, measure voltage between ground and terminal No. 9 (Red/Blue wire) at ECM harness connector E8. See Figure. For heated oxygen sensor bank No. 2 sensor No. 2, measure voltage between ground and terminal No. 14 (Black wire) at ECM harness connector E7. Voltage should be 9-14 volts. If voltage is not as specified, go to next step. If voltage is as specified, replace ECM.
- Turn ignition off. Disconnect appropriate heated oxygen sensor No. 2 harness connector. For heated oxygen sensor bank No. 1 sensor No. 2, measure resistance between terminals HT (Red/Blue wire) and B+ (Black/White wire) at heated oxygen sensor No. 2 connector (component side). See Fig 1. For heated oxygen sensor bank No. 2 sensor No. 2, measure resistance between terminals HT (Black wire) and B+ (Black/White wire) at heated oxygen sensor No. 2 connector (component side). Resistance should be 11-16 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace heated oxygen sensor No. 2.
- Repair wiring between ECM and heated oxygen sensor No. 2, or between heated oxygen sensor No. 2 and EFI relay. See WIRING DIAGRAMS article.