Re: Crankshaft Position Sensor replacement - it's in but

GM service publications state otherwise.

Or; even if it is mounted correctly.

Or if you merely replace it, or the timing cover. RTFM.

Time better spent understanding the service procedure(s).

What does the rest of the auto industry do when replacing magnetic pickups?

Or if you want to pay for it, you of course can.

What happens if you do not do the relearn?

Won't argue knowledge is power :)

Well, some follow the recommended procedures and some don't follow the recommended procedures. The ones in the latter choice are usually left wondering why the vehicle doesn't perform as it should/why parts failed. Then I make money off of them.

Or; if you don't want to pay for it, you can pay even more money when the collateral damage occurs.

Ignition timing will not necessarily be correct, misfire monitors will not be accurate. Possible bad results; broken piston rings and/or ring lands, worn or deformed rod bearings, clogged/melted/plugged catalytic converters, excessive emissions, emissions test failures, damaged spark plugs, phantom driveability problems/phantom trouble codes. (just to name a few)

If the service procedures call for a realearn or resynch:

Professionals like us have the proper equipment and do it the way it is supposed to be done.

Buy a scanner if you're going to give any advice, and I suggest you get some update information so you can learn for your self.