I new getting a C5 I was going to run into all the common problems, especally with a moderate mileage (43K) mostly weekend car. I have already budgeted for fixing these common things.

I've had the car since Saturday and this morning coming out of my parking garage over a few rough little bumps (metal guides for the gates) I got the ABS/Traction control message and lights.

Shut the car down, restarted lights and messages went away and did not come back up on the way to work (1.5 miles)

At lunch I made it about another mile before it came back on. I pulled the codes and got the following. I also reset them to see if the same ones would come back.

C1221 (wheel sensor)
C1222 (wheel sensor)
C1226 (wheel sensor)
C1248 (DRP disabled)

On an errand after lunch about 12 miles later the error message popped up again after going over some more rough pavement and when I got back to work I pulled the codes again and I have only the C1221 back.

Does this sound more like loose or corroded ground or an other EBCM issue? If it's the EBCM I would like to send it off before GM takes back my GTO so I do not have to borrow a car.

Thanks in advance