Battery Reset

[NalgonaZ71]

Allen,
I read in another thread that disconnecting the battery for a length of time will reset the PCM. How Long is that time? I would hate to wipe the great tune I got from you. Doing a battery change.

Thanks

[SlammaDingdong]

Originally posted by NalgonaZ71@Jun 22 2005, 09:51 AM
Allen,
I read in another thread that disconnecting the battery for a length of time will reset the PCM. How Long is that time? I would hate to wipe the great tune I got from you. Doing a battery change.

Thanks

First I'm not a GM PCM expert and know little about the actual hardware internals or program algorithms.

You don't lose the PCM tune itself [which is really just a number of parameters/maps used by the computer program that controls your truck]. What you lose is the "learning" the PCM program has done since it was last reset. There are various "tables" that get updated in real-time as you drive, based on many factors. This dynamic information stored by the computer is meant to continuously optimize performance over time.

I'm not sure how much time you have if power is disconnected, as I don't know what type of memory is used in the PCM. I've heard some say it takes several hours, others say a few seconds - I think it may depend on the model year too. I've also seen a variety of procedures for forcing a reset. I'm not sure, someone else may want to chime in here. My guess is that for late model PCM, the reset is almost instantaneous.

Bottomline, it's not a problem. The computer will "relearn" as you drive.

Also, best practice is to always disconnect power when doing any mechanical or electrical work on your truck. If this caused us to lose PCM tuning every time, then Allen wouldn't have time to sleep

[TXsilverado]

thats why ive been putting off the optima im just having too much fun, and dont want to wait another 400 miles

[RedHeartbeat]

If the disconnect the battery thing was an issue and would cause you to lose your tune, Allen has been cheating all of us mail order customers out of a killer tune!!!!!

[SlammaDingdong]

Originally posted by TXsilverado@Jun 22 2005, 01:16 PM
thats why ive been putting off the optima im just having too much fun, and dont want to wait another 400 miles

Man I hear ya' there. I now try to combine work i'm doing into one session. You know, get something done, and then a few days later you're like, "Crap, I gotta unhook the damn battery again!"

[NalgonaZ71]

Thanks Guys I didn't think that it would wipe the tune. I justed wanted to ask. This is the first time dealing with a PCM program and I am like you TXS I am having way too much fun to lose it.

Fred