I have a SES light and the code is a P0315 and it says quote,"Crankshaft position system variation not learned." What does that mean? Just curious if it has something to do with the tune. I have a Nelson ECM that has been in there since the end of June so maybe 2,000 miles. Thanks

 

Sounds like you need to do a crank re-learn. Seems a little odd it took so long to set the SES light, but I wouldn't be too worried yet. If you can find someone close to you with HP Tuners or EFI live they should be able to do the crank re-learn for you.

 

actually mine did the same thing with my old nelson tune...was about 2 months before the crankshaft relearn code came up.

 

What do I do?? Do I have to get a new PCM?

 

No you just need go through a simple routine that resynchs the pcm to the crank position. It only takes a couple of minutes for someone with Hp tuners or EFI live to do.

 

Or a GM dealer with a Tech 2 can do it, but that will most likely cost $$$

 

And it sucks to have to pay money for something that only take like 2 minutes...

 

Ok so I still don't know how to do it.

 

You have to find someone with EFILive, HP Tuners, or take it to a dealer and they can do it with a Tech 2. Basically, they plug the scan tool into the diagnostic port on your truck and run the relearn program. It's very easy.

 

You can continue driving your truck, it sounds like it's running fine.
Just take your time finding a shop and you'll get a good deal on it.

The process is easy, find someone with a TechII or similar and have them hook up to the diag port. They'll simply go through the menu and then rev the engine to less than 5,000rpms and the light will go away.

good luck,
allen