Diagnosis & Repair
WARNING: This page is about a different car, the 2003 Lexus RX 300. However, it is still accessible from the selected car via links, so may be relevant.
- Test drive vehicle and check operation of speedometer. If speedometer is not operating correctly, repair speedometer as necessary. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. If speedometer is operating correctly, go to next step.
- Access ECM behind glove box. Turn ignition off. Disconnect ECM E6 connector. See Figure. Using voltmeter, check for continuity between ground and terminal SPD (Violet/White wire) at ECM E6 harness connector. If continuity does not exist, go to next step. If continuity exists, locate and repair short to ground in Violet/White wire between ECM E6 connector and instrument cluster.
- Turn ignition on. Measure voltage between ground and terminal SPD at ECM E6 harness connector. If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, locate and repair open in Violet/White wire between junction connector IJ1 and ECM. See Fig 1. Connector IJ1 is a 16-pin connector located behind glove box.
- Check for open in Violet/White wire between junction block No. 3 and instrument cluster. See ENGINE PERFORMANCE in WIRING DIAGRAMS article in ELECTRICAL. Repair wiring as necessary and retest system. If wiring is okay, replace ECM and retest system.