Diagnosis & Repair
- Test drive vehicle and check operation of speedometer. If speedometer is not functioning correctly, see the INSTRUMENT PANEL article in the ACCESSORIES/SAFETY EQUIPMENT section. If speedometer is functioning correctly, go to next test.
- Access ECM behind center console. Disconnect cruise control ECU harness connector. Cruise control ECU is behind left air duct. Move shift lever to neutral.
- Lift and support front of vehicle. Turn ignition on. Using DVOM, backprobe ECM connector. Measure voltage between terminal SPD and ground, while rotating front wheel. See Figure (M/T Calif.) or 10 (A/T Calif.) or Figure (A/T Except Calif.) or 13 (M/T Except ).
- Voltage should pulse between zero volts and 4.5-5.5 volts. If voltage is within specification, replace ECM and retest. If voltage is not within specification, inspect circuit between ECM and combination meter. See wiring diagram in the WIRING DIAGRAMS article.