I logged a friends 2008 GMC Sierra last night and after doing a PCM read (high speed checked) the truck started giving a U0101 "Lost comm with TCM" code. The truck will crank but will not shift when driving.
Can anyone give any insight how to correct this issue or if it is possible HPTuners did anything to the PCM and/or TCM? My EIO is not licensed to write to this PCM so I don't see how I could have written anything to the truck.
Please help.
Just wanted to add, it was late last night when this started happening. I suggested to him to park the truck and disconnect the battery in hopes this would reset everything. We have not tried the truck this morning yet.
Try disconnecting the battery & or tcm fuse for 30 seconds, TCM probably needed to be reset after the read.
It doesn't have to be perfect, it just needs to be done in two weeks...
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Thanks Bill. As I said in the 2nd post we did disconnect the battery over night. I just spoke with my friend and that cleared up the problem. Is this an HPTuners bug or a problem with these TCM's?Originally Posted by Bill@HPTuners
Problem with the TCM. You always have to do a reset after a read. Don't know why though.
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