I finally converted my 2001 Vette to use os 12212156 and cos0202005. The Car runs perfect and on a nitrous tune there are no issues. I'm using my window switch to activate the nitrous/fuel relays and pcm pin 56 sink relay. The pcm no matter what settings I try will not retard timing when the pin 56 input is grounded. I have 10.96vdc at the wire connected to pin 56 measuring open circuit, and 12.5 volts on the pcm supply when the vehicle has key on but not running. Any suggestions? I've tried activating it and different MAP and RPM levels with no success. I know there are 2 out of range cos parameters, but I can't get them to clear even when adjusting the values in range of limits.Attachment 12815