Thread: Slipping? or PCM re-learn?

So my battery died today, jumped it off and everything was fine, but...... My tranny feels like it's slipping between 2nd and 3rd. It gets up to rpm's fine but when it goes to shift it just kinda holds itself there for a few seconds and finally shifts. Did the PCM reset itself and has to re-learn or am I in deep doodoo? I have service records of a flush and filter change at 75k, and the car has 167k on it now. It doesn't seem to be getting worse, but it's not getting any better.....

When batteries go dead, the pcm will likely lose it's memory of adaptive shifting etc. Give it a little time to learn. If that doesn't help. Unhook it, touch the battery cables together and maybe it clears and relearns.

Thanks. I drove 80 miles last night and it still didn't get any better, thats why I was getting kinda worried....

I have had cars in the shop do the same thing after doing engine service and the battery was unhooked for a while. More times than not- when you need the transmission adapts to reset with a trans install they dont reset and you have to do it with a scan tool, go figure. Unfortunately your pcm has been learning for a very long time as your transmission ages and adapts to this. I have had cars that even after a week of stop and go driving just dont feel any better or at all like they used to and had to tweak the tune a bit just to get them back to normal. 167K miles is not on your side and it is going to take time to relearn but may be out past the point of no return and the quick easy bandaid is installing a Transgo shift kit as that has proven to help out more times than not in situations like this. The more shift cycles and key cycles the car gets the faster it learns, so if you do a lot of highway driving it is going to take a long time to get back on track if it does at all. It is best to try NOT to drive the car hard if you dont have to until things start to feel better.

Thanks for the help. I drove the car to work tonight and it seemed to do it less often. I guess it wouldn't hurt to do a flush and filter change. I went WOT last night and it shifted fine it only seems to do it when under normal driving, i try not to let the rpms go over 3200. Im just glad its nothing major.

Originally Posted by JESSEGOTTA GP GT

Thanks for the help. I drove the car to work tonight and it seemed to do it less often. I guess it wouldn't hurt to do a flush and filter change. I went WOT last night and it shifted fine it only seems to do it when under normal driving, i try not to let the rpms go over 3200. Im just glad its nothing major.

hmm. well everytime i unplug my battery cables, mine has to re-learn again as well. however, mine doesnt shift problematic as does yours, therefore i just drive aggressively in the city for a little bit and usually on the 3rd key cycle or so the shifts firm up nicely.

on the other hand, randomly my car started doing the same thing as yours except it was gear 1-2. it would just sorta hang between gears then decide it wanted to shift, and it occurred most frequently under lighter throttle than not. and i did a pan drop/filter change and it cleared that problem right on up.

so theres some food for thought.

I guess I'll be doing that this weekend. I've been planning on doing it since I got the car.