Saturn Repair Problems? Ask a Mechanic for Answers ASAP
Hello, my name is Bobby. Thank you for the question. Can you tell me if the check engine light is coming on when this occurs? Does it happen every time you drive it?
Thanks for getting back with me. It sounds like an electrical issue. Most of the time this is caused by the ignition switch or the body control module. I would start by checking the ground connections on the engine, and especially the connections on the negative battery cable to ground.
If the sensor was changed and it continues to bounce around then you more than likely have a wiring issue from the sensor. Do your scan tool have the ability to see live engine data to see what the computer is seeing when this occurs? If it does then see if the speed in the computer is showing the same. If it is then the wiring is either failing or it can be the PCM. Did you check the connections at the PCM?
It is the PCM. As for other sensors it only has one vehicle speed sensor but it also have input and output speed sensors, but those do not affect the speedometer
Are you able to have the speed signal verified with a scan tool?