PCM reprogram for crank position on 2004 Chevrolet Tahoe

My GM dealer reprogramed my PCM because the crank position sensor needed to be reset. Seems like the check engine code would come on if this needed to be done or the car would not drive correctly! Any ideas?

Asked by for the 2004 Chevrolet Tahoe
Two of my vehicles had to have the computer reprogrammed, One wasn't shifting right and the other was a recall to reprogram when I dropped it off for a EGR valve replacement and either one had a check engine light on.