Q&A

 Master

The speedometer operates from a speed sensor on the transmission. The speed sensor (VSS) produces an ac signal that increases with road speed and is interpreted by the speedo head in the dash to indicate speed at the instrument cluster. If the VSS fails the cruise control will not operate and the Check Engine/Service Engine Soon Light should come on. If the cruise control works normally or a scan tool reads MPH the speedometer head is probably faulty.