1998 GMC Sonoma Q&A
1998 GMC Sonoma Question: Trouble code "transmission module unstable".
stop clearing the code and take it to a shop so they can see the freeze frame data to help them determine the problem. unless you have a scan too that can acess the info for the trans, throwing parts at it can be very expensive. Roy - mastertech6371
Trouble code "transmission module unstable". What are possible fixes? Where is transmission module?