this came up for abouta hundred miles today then went away. the abs was a light. any thoughts it wet away for now and i wasnt towing.

Check your wheel speed sensors. They are the little wires connected to the upper control arms of the truck that go down to the hub assembly. When I put bigger tires on my truck apparently the wires wern't being held in to the very chinsy wire tie holders gm provides for us. On full crank the inside of my tires were hitting the wires slowly rubbing off the coating on the wire. As soon as I hit a bump or turned and the wire grounded out on the upper control arm, the light came on. As soon as the problem self corrected, and truck was turned off, light re-set it self. GM replaced both wheel speed sensors once and told me it was my fault and it would not be covered under warranty again! I used some wire ties, rubber fuel line, and some electrical tape. They won't wear out again:D

The trailer brake controller is having issues - even without the trailer. Either the trailer brake circuit has a short, could be from water in the plug, or the brake controller is bad. Have your dealer check it out. The ABS light could be related or a separate issue.

If your ABS is failed, you will set the Service Trailer Brake message. The Integrated Trailer Brake uses the same signals as the ABS.