I would shut the engine off and the speedometer, and Tachometer said the engine was still running. I made an appointment to have it looked at. No codes. It happened intermittently. They couldn't diagnose it unless it was happening. It took about 12 trips to the dealership before they finally saw what I was talking about. They traced it to a radio problem. They replaced the radio - and the CD player doesn't work in the "new" radio. Fixed the problem though. Why are dealerships stuck on codes and assume the customer is lying? Every time.