Quote Originally Posted by Wraith888 View Post
I had not heard of a case learn before. I did some searches and other places I'm reading that you need to do a case learn if you are replacing the CPS. Is that correct? From what I read on this how-to and Bill's most recent post, it sounds like not really. Can anyone clear this up and also explain more in-depth what a case learn is? (a link to a good explanation is fine too)

Current symptoms: Car has been having issue where it may or may not hesitate while driving down the road. If it does hesitate, car runs uneven and jerks slightly, then recovers within a few seconds, then a few moments later the tach drops to 0, then about 10-30 seconds later the traction control off light comes on. Car continues to drive fine and when I shut it off and turn it on again, the tach works and the traction light is off indicating everything is fine. It's been doing this for a couple years, but it seems to be happening more often, and looking online it seems this is classic indications to replace the CPS, so I was planning on doing that tomorrow.

Car: 2000 Pontiac GT
the purpose of the crankshaft variation relearn procedure is for the pcm to compensate for differences in the signal output from one crank sensor to another. If this is not done you may get false misfire dtc's at high rpm's.