2007 Yukon XL Codes P0455 P0449

[polonash]

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?

Thanks in advance for the help.

 

[gnarpow]

The engine lights need to be cleared with the code reader, they will usually not go away right away if you fix the problem and don't manually clear them.

No idea about your morOnstar problem

 

[polonash]

Both issues were fixed by disconnecting and then reconnecting the battery. All is well now.

By the way anyone who runs into this problem and buys the new superseded part to fix it will notice the wire connectors don't match up. You will have to buy the wiring harness adapter to get it done right. I waited a few months to post my results to make sure I had fixed this issue correctly and I'm glad to say this did it. No more check engine light!

 

[Most Hated]

Can u post a link to the parts used?