I was seeing if anyone had run into this issue? The car will start if you turn it all the way to crank position then turn it off quickly and back to run. to use a scan tool you have to be in the acces position. in the run postion the modules all power down. there are no reverse lights either. all ready replaced the bcm and ignition switch. If anyone else has any idea where to look for the problem let me know. Thanks

I am not sure if I understand what problem you are describing.

Also what vehicle is this since there is no 2004 G6, it started in 2005 model year.