Do I Need a CASE Learn?

[Mr. INTENSE]

You DO need to perform the Crankshaft Variation Learn procedure if you physically install a new PCM, replace the crankshaft, camshaft, timing chain, crankshaft position sensor or balancer.

You DO NOT need to perform the Crankshaft Variation Learn procedure if you have new code flashed into your current PCM.

Scott

[GP_Pimp]

Scott
If you could explain a little further on exactly what a Crankshaft Variation Learn is I would appreciate it. I think my understanding of it is a little off. Exactly what variance is it going off of? Crank to Cam?

[Justin@Caspers]

The crankshaft position system variation learning feature calculates the reference period errors that are caused by slight tolerance variations in the crankshaft, the crankshaft balancer interrupter rings, and the crankshaft position sensor hall effect switches. The calculated error allows the PCM to accurately compensate for reference period variations. This enhances the ability of the PCM to detect misfire events during a wider range of engine speed and load conditions.

The crankshaft position system variation values are stored in the PCM non-volatile memory after a learn procedure has been performed. If the crankshaft position system variation values are not stored in the PCM, DTC P1336 will set. The learn procedure is required after the following service procedures have been performed:

PCM replacement
Engine replacement
Crankshaft replacement
Crankshaft balancer replacement
Crankshaft position sensor replacement
Any engine repair which disturbs the crankshaft or the harmonic balancer to crankshaft position sensor relationship.

[PacerSS]

alright so since I swapped cams and installed a new PCM I definately need one then wouldnt you say?? I got an 0500 when I first cranked the car after swapping the PCM(it didnt do that after the cam so I figured I was good) but since you say that I need it so be it. Thanks for the info man.

[1Hot97]

Don't forget to mention that 97's don't need a case learn with a PCM swap.

[Mr. INTENSE]

Don't forget to mention that 97's don't need a case learn with a PCM swap.

Right. On the 1997 cars, just swap the Knock Modules and you're all set.

[GP_Pimp]

Thanks for the info Justin. Things are much clearer now.

[Justin@Caspers]

Don't forget to mention that 97's don't need a case learn with a PCM swap.

Assuming you swap the knock module. If you do not, you need a case learn. Also, if the crank sensor has been replaced, you need a case learn anyway with a '97.
HTH.
--Justin

[harps500]

I went to the dealer to get a case learn on my 97 yestarday. They said it wasnt needed. I tried to explain that when you replace the sensor you do need it done but they wouldnt take my money! Are you sure they need to be re-learned after new sensor?