Drivers info center.....

[Doubeleive]

Can you just unplug these and spray and reinstall?

yes just be careful there is a little clip if you break it good luck finding that connector, I got lucky and my dealer parts guy found it only listed as "genuine gm connector" no part number listed anywhere.
to the op when you hook up the tech2 and scan for DTC's the trouble code should point you right at the problem. mine was also a loose connection at the front right strut.

 

[Doubeleive]

yea I get that message everytime I start ours too. We have a bad compressor and bad rear shock badders. Our Denali still drives like a dream. If I pulled a trailer I would spend the $900 w/Rock Auto and fix it.

that's weird even with my rear shock's being a little low on air I could feel the difference driving down the road, freaking thing was wagging it's tail, but I drive the thing like mario so....