I've had a Wheatley tune since 07 on my 03 GMC. If the main battery dies for whatever reason I have to go through a complete relearn cycle. I was wondering if anyone knows why the PCM wont store the relearn even with dead battery. Seams to me the PCM would have an internal battery to store this information. If so maybe it is dead or failing. This problem reminds me of when a computers motherboard button battery fails and you have to reset the date and time everytime you take the main battery out.

Thanks for reading.

 

All the GM relearns
http://www.bsecorp.com/files/techtips/ST9303l.pdf

Certain info is kept in teh KAM(Keep ALive Memory). Not sure what all that entails though.

peace
Hog