Wednesday, October 17th, 2012 AT 10:51 PM
I have a 2007 GMC Yukon XL Denali with a check engine light on. Advance Auto checked the codes which are P0449 & P0455. I have not had any gas cap tightening issues. I read lots of posts all over the internet that led me to replace the EVAP valve/solenoid. I used a newer improved version from Amazon. After physically installing it I went to plug the wiring up but it didn't quite match up but I got it to go which may be where the problem is? The light didn't go out but I also noticed that Onstar was no longer working as well. No lights on the mirror at all no matter which button I push? I thought maybe I had made a mistake by forcing the wiring connector together so I unplugged it and went back to the internet finding a little harness made for this issue. The problem is when I plugged it in I still don't have this thing fixed. The engine light is still on and Onstar has no power. Any ideas?