Whats the TRUTH behind a case learn??!! - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


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Old 04-20-2006, 01:29 AM   #1
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Default Whats the TRUTH behind a case learn??!!

http://www.zzperformance.com/grand_p...ts1.php?id=182


Now as ZZP states, a case learn is NOT needed IN MOST CASES (as I have stated before). But is recommended (also as I have stated before).

Even GM the builder/designer of our cars, even states a case learn is NOT nescessary. Most of us are modding so I would recommend one anyways.

So whats the TRUTH????????????



This has nothing to do with a new product(since they don't have one for a Bonne), just REAL info that backs me up on my experiences!!! That is all.

Thank You
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Old 04-20-2006, 02:40 AM   #2
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since the INTENSE pcm was installed by the previous owner, the car has not had a case learn.. then when i swapped the 98 gtp motor in it, it has yet to get a case learn again.. i wil be doing it soon, and will gladly report my findings
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Old 04-20-2006, 08:56 AM   #3
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There may very well be a difference on this between a GTP PCM and a Bonneville PCM.
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Old 04-20-2006, 10:10 AM   #4
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Interesting info regarding CASE learns.

Recently we heard that it helps with KR etc- slightly.

We have heard it "should" be done when putting in a new pcm or if the crank has moved at all when the car was not turned on.

The other day I asked my good buddy Mechanic Dan about the CASE learn and the necessity of it. (Background on Dan: ASE Certified, Dealership tech for 15+ years, worked at Pontiac/Cadillac dealer from 93-98, keeps up on his credentials and education continually now that he owns his own shop. I've yet to see him give up on any job. He researches, and located the root cause.)

His response was this "If the car runs fine and does not appear to have any issues a CASE is not necessary. You will probably not need a CASE learn in most cases, however it the car runs poorly then have one done."

With that said..he is a mechanic and not a performance tuner. He has no opinion or background to performance tuning. Only that his experience and training says if the car runs good and all parameters are where they should be..then CASE should not be necessary.
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Old 04-20-2006, 10:37 AM   #5
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Quote:
There may very well be a difference on this between a GTP PCM and a Bonneville PCM.
There are many differences as we all know, but from going thru the PCMs, I havent noticed anything that would wouldnt make this true for the Bonne also

The ONLY that may play factor is the Bonne'* security features, but all that points at retarding timing with any issue.
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Old 04-20-2006, 11:25 AM   #6
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A case learn is more or less where the PCM learns the true position of the crank... If you have diconnected the PCM and or altered the Crank position, replaced the crank sensor, replaced the engine.... Replaced the PCM..... Then a Variation Learn sequence should be performed...

Without it chances are that the car will run, and in some cases pretty good... But it will not be completely correct...

If you have in no way altered the PCM, the engine or Crank sensor then you shouldn't need a Variation learn performed..

I can't believe that GM service Mechanics don't know what a Case learn is, thats just nuts

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Old 04-20-2006, 11:38 AM   #7
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On all gm vehicle that have the option do to a case learn built it to the pcm it is recommended when ever the crank sensor is removed or replaced and when a pcm is replaced that it be done. That'* straight out of the SM'*. I could get the exact wording if it'* needed. When I do pcm updates to correct service issue'* it tells you that a Crank relearn may be necessary. Sometimes I have to do it cause it sets a code and sometimes it don't. When it doesn't set a code I don't do it. At the dealership it'* usually called a crankshaft position sensor relearn. The DTC that sets is a P1336 which says crankshaft position system variation not learned. I just check and my 00 can set a P1336. So I say on, at least all 00+'* that do a pcm it needs to have a CKP relearn done. I have seen cars that had random and multiple misfires at idle and under load fixed by doing a CKP relearn.

I will do some more checking in a little bit but IIRC all OBD II cars it is recommended by GM to have one done.
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Old 04-20-2006, 11:54 AM   #8
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We would all be surprised at what GM techs learn due to flat rate pay scales.
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Old 04-20-2006, 12:33 PM   #9
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While it may not be needed in all cases, it should be considered as a 'best practice' whenever the PCM or CPS are replaced.

Often when tuning you're dealing with many parameters and potential causes of KR and whether they orinate from the engine or Torque Management, by performing the Crankshaft Position Variation Learn Proceedure (commonly referred to as a CASE Learn), you then eliminate a potential source of problems.

Cheers,
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Old 04-20-2006, 12:35 PM   #10
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Back when I had just got my DHP and gotten oil change at Grand Pontiac[one of the biggest GM dealers in michigan], Four of their techs kinda looked at me with blank stares when I mentioned CASE learn. So its not unlikely alot of them havent had to do one or have a clue what it is. I think its a case of GM dealerships and regular garages that dont do performance modifications or complete engine rebuilds or replacement, dont have a clue.
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