LS Case Relearn

onetoncrawler · Sep 28, 2010

While riding last Saturday I got a SES light, came home and checked it and got a P1336 Crankshaft Position (CKP) Sytem Variation Not Learned.

after doing a lil research (GOOGLE) i found out that the cam position and cranshaft position are unknown to the comp and i need to do a re-learn procedure to get those back into sync.

seems to be a common problem with a tuned computer :dunno:

i sent my comp/harness to Jim's and figured i was done, has anyone ever dealt with this??

can i do a case re-learn with my Cen-Tech 98614? or do it without a scan tool?

Thanks

hinton · Sep 29, 2010

i have 3 tuned ls1 engine/computers sitting in my driveway and have never had a problem like that

onetoncrawler · Sep 29, 2010

http://www.trifectaperformance.com/tech/crankrelearn.htm

anyone have a tech 2 scanner? I'm going to call Jim today but it almost sounds like the computer needs to be hooked up for the problem to be solved

patooyee · Sep 29, 2010

HP Tuners can perform a case relearn. I'm new to my VCM suite but a small amount of research on their forums shows it to be fairly simple. Find someone with HPTuners who will come to your place and do it. Its a scanner, not a tuner, function so it shouldn't have much ris of screwing anything up. I don't think you're local to me or I would offer to do it.

J. J.

patooyee · Sep 29, 2010

Here's some more info from HPTuners' forums:

This thread indicates that it may be possible to do without any software:
http://www.hptuners.com/forum/showthread.php?t=1260&highlight=crankshaft+relearn

Then this one says it isn't and that you have to have software and a scanner hooked up:
http://www.hptuners.com/forum/showthread.php?t=1069&highlight=crankshaft+relearn

One more:
http://www.hptuners.com/forum/showthread.php?t=9299&highlight=crankshaft+relearn

I'm glad you brought this up because I'm not using the original ECM with mine so chances are high that I will have to deal with it soon.

Basically, every crankshaft reluctor wheel has minor machining variances in it that makes it unique to each engine. If these variances are far enough outside of the programmed range the computer thinks its receiving thousands of tiny misfire codes. You do the CASE relearn to teach the computer these vriances of your specific reluctor wheel hence the reason the issue is more common in engines without their original ECM's. You may have to do up to 3 relearn procedures for it to work.

J. J.

onetoncrawler · Sep 29, 2010

thanks for the information :dblthumb:

this info explains why i got random misfire codes when i first ran the engine. it seems to run fine now, but it did surge a little when the light first came on so i may be one of the few that experience some issues with the code other than the light coming on

Jim said he could delete that read, which would make the code disapear forever but i would like to use that as a last resort

im in North Bama - if anyone has a tuner i would appreciate it.

patooyee · Sep 29, 2010

I wouldn't delete the code. I would just fix it. Otherwise the computer will never be able to get the timing right I would think. If worse comes to worse just take it to GM and have them do it. Are there any dyno shops near you? Call them and ask if they can do a case relearn.

J. J.

onetoncrawler · Oct 12, 2010

patooyee said:
I wouldn't delete the code. I would just fix it. Otherwise the computer will never be able to get the timing right I would think. If worse comes to worse just take it to GM and have them do it. Are there any dyno shops near you? Call them and ask if they can do a case relearn.

J. J.

took the buggy Friday to a local shop that said he could do a case re-learn no problem. He hooked up the computer and when through the motions but it wouldnt let him start the procedure......

couple of things it kept asking for (that i couldn't do) was apply the brakes and ensure vehicle is in park, im not sure if the computer has a brake sensor... i know those motors have a park sensor but Jim knew that i was running a TH 400 so he deleted those wires

I guess the new question is, can this be done to a computer that has be altered?

Some other good info (I hope) , the guy said that this would not cause any problems unless i had a misfire, he said it would cause the computer to not be able to recognize a mis-fire and shouldnt hurt the performance of the motor.

i went ahead and rode Saturday and it seemed to do fine :dunno:

patooyee · Oct 12, 2010

The GM Factory CASE relearn, I BELIEVE, requires the brake to be on, vehicle to be in park, and coolant temp to be at a certain point. From what I understand, different versions of HPTuners have bypassed some to all of these requirements and the most recent version does not require any of them. You may wish to do your own research on that though as this is just hazy info recalled from my previous searches to help you out. But if its true that means only the most recent verison of HPTuners will do your CASE relearn. It is free for HPTuners owners to upgrade versions. That or get your ECM pinout and find where the wires are for your brake and park switches and short them to power or ground, whichever they may need.

I'm one of those guys who can't live with a ck engine light on though.

J. J.

onetoncrawler · Oct 12, 2010

patooyee said:
The GM Factory CASE relearn, I BELIEVE, requires the brake to be on, vehicle to be in park, and coolant temp to be at a certain point. From what I understand, different versions of HPTuners have bypassed some to all of these requirements and the most recent version does not require any of them. You may wish to do your own research on that though as this is just hazy info recalled from my previous searches to help you out. But if its true that means only the most recent verison of HPTuners will do your CASE relearn. It is free for HPTuners owners to upgrade versions. That or get your ECM pinout and find where the wires are for your brake and park switches and short them to power or ground, whichever they may need.

I'm one of those guys who can't live with a ck engine light on though.

J. J.

ive been reading up on those tuners and think i may have a lead to a guy that has one.

will see soon