I have an 04 Z06 Comm. Ed. with 18,000 miles and this is my first time back to the dealer since I purchased it new. Had oil leak on left side of rear axle which they repaired under warranty. According to my service invoice the dealer performed campaign 04006 "nec to reprogram PCM and perform funtional test per campaign". What does this mean? The service person was quite vague in his response other than it was mandatory and there was no choice since the car was in for service.