do I need to do a crank relearn?
 

I put the new PCM in last night, did the security relearn. Everything is great and I don't have any codes or lights to speak of.

Then no, probably not. Do you have access to software?

No, I don't. I don't want to pay someone to do the relearn if it isn't necessary. There's no lights or codes.

You should still do a relearn, yes.

will I do any harm with light driving? I cant get this done until next week.

no. If you have no code it isn't necessary. You can do it for S&G but when I had a mail order tune I never did one.

YES!! you need to get the crank relearn done! especially if it's not the original pcm from your truck originally... do it!

"A CASE relearn is an advanced way for the truck to detect misfires, based on the relationship of the cam position sensor to crankshaft position sensor. Anytime you permanently intend to install a PCM that did not come directly out of your truck, you need a CASE relearn."

well then it appears I am misinformed. I will concede to the experts. :hail:

Whenever you replace a crank, cam, pcm, timing chain set, cam sensor, crank sensor, etc. YOU MUST DO A RELEARN. As I've stated in other post, I do this on high mileage trucks for people and often times will even see them run better since the injector firing, spark timing is more accurate.

Sure, but in my experience it wasn't a "requirement" when swapping PCMs.

Easy enough to do if you have the right software. ;)