My speedometer, odometer, and heads up display stopped working one day after the speed jumped up and then back down. I took it into the speedometer shop and they spent 3 days on my car, first they changed out the whole dash thinking that was the problem and they were wrong, so they put mine back in and it turned out that the junction box under the hood was dirty. They still charged 140 to clean this. I guess that is better than charging for their miss diagnosis. I didn't know how fast I was going, except to go off of RPM's and listening to it shift and what I was really worried about was the fact the odometer wasn't reading my miles.