Diagnosis & Repair

WARNING: This page is about a different car, the 2003 Lexus LX 470. 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.

NOTE: VSS input circuit between instrument cluster and ECM is a Violet wire at terminal No. 17 at ECM harness connector E9. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

Fig 1: Locating ECM Connector Terminal SPD

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: Identifying 4-6 Volt Intermittent Pulse

Access ECM behind glove box. Raise and support one rear wheel. Turn ignition on. Place shift lever into Neutral. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal SPD of the ECM connector. See Fig 1. Observe voltage reading while rotating rear wheel. Voltage should pulse between zero volts and 4-6 volts. See Fig 2. If voltage is as specified, replace ECM. If voltage is not as specified, repair open or short in wiring between instrument cluster and ECM. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.