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 ECM harness connector and measure voltage between ground and terminal No. 9 (Red/Blue wire) at ECM harness connector E6. See Figure. 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 heated oxygen sensor No. 2 harness connector. Measure resistance between terminals HT (Red/Blue wire) and B+ (White wire) at heated oxygen sensor No. 2 connector (component side). See Fig 1. 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.
- Check wiring between ECM and heated oxygen sensor No. 2, or between heated oxygen sensor No. 2 and EFI relay. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, repair ECM power source circuit. See WIRING DIAGRAMS article.