Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › Speedometer gone whacko! › Speedometer gone whacko! December 26, 2019 at 12:16 am #895597 college manModerator check engine light on or abs? With a scan tool, take the vehicle for a ride and see if the MPH is read. If not seen then vss would be suspect. check the vss connection at the rear tail shaft of the trans.