VSS No. 1 Circuit (Speedometer Operates)
WARNING:
On LS400, removing cover from rear of instrument cluster will expose screw heads "a"-"f" and connectors "K", "P" and "Q". See Figure. These screw heads and connectors are part of the cold cathode tubes in the cluster. When power is supplied to cluster, DO NOT
touch these connectors and screw heads because they are electrically charged with high AC voltage.
- Remove instrument cluster, but leave electrical connectors attached. Raise and support vehicle with rear wheels off of ground. Turn ignition on. Connect voltmeter between chassis ground and terminal No. 9 (Violet/White wire) of instrument cluster right connector ("right" as viewed from rear to front of vehicle, with instrument cluster installed). Rotate drive shaft.
- If voltage does not alternate between zero and 5 or more volts for each revolution of drive shaft, go to next step. If voltage alternates between zero and 5 or more volts, check for open or shorted Violet/White wire between instrument cluster and ECM. See COMPONENT LOCATIONS under INTRODUCTION. If Violet/White wire is okay, replace ECM.
- Remove cover and power source unit from back of instrument cluster for access to printed circuit. Check for continuity between the following speedometer terminals of printed circuit. See Fig 1. If there is no continuity, replace printed circuit. If there is continuity, replace power source unit.
- "A" and b9
- "B" and a7
- "C" and b11