Not sure if this is the right place to post this as I am new but I just bought an 06 grand prix gxp, upgrade from 00 GP gtp, and I'm having a slight problem. Apparently there is a p0573 code that the transmisson place that I took it to found but the problem I'm having is that the cruise control will not work and tcc will not lock up. Cruise will flash on for a split second then back off. I have replaced the brake light switch but did not fix the issue. Brake lights light up fine, not sure if the issue could be that they are new LEDs and a new spoiler with 3rd brake light, I added resistors to the 2 LED brake lights but still nothing. I took to the trans shop because it was reaching 235 degrees during 30min+ highway driving, they thought the brake light switch would solve both problems because if the tcc will lock up it will cool the trans more and the cruise will work again. Thanks