While towing yesterday my warning light for the ABS and brake system sounded. The dash says to service the brake system. I checked the fluid and it was good. Anybody know what this warning is for? I had checked the pads on all four axles last month during a tire rotation. 2003 Duramax with 120k miles.

Thanks

Could be a wheel sensor gone bad....with cars and computers now a days it could be the simplest thing that will set off a warning light. If you have an AutoZone near by go in and have them check the computer for codes....its free and they will let ya know what the deal is..

Was it during braking? Did the system engage/cycle?

Take it onto some gravel and brake hard. If it works, don't sweat it. If it does it again, have someone pull the code for you.

It still brakes fine. I was not braking when it started. Infact I was rolling downhill. It just keeps setting off with that anoying buzzer. I was thinking a bad sensor also. No codes from the computer.

A lot of the GM trucks have an issue with rust under the frt wheel sensors but I'm not sure if you have removable sensors or not. (some are part of the hub) Pull a wheel, follow the wire, if the sensor is bolted in pull it and clean the area where it mounts real good, put a little grease there and reinstall.

My truck has the same thing going on with it. I just had the truck in for service and the told me of no brake codes. It has happened on my truck probably 8-10 times. I just had my brake checked and even had the rotors turned and everything was fine. I also had both front hubs replaced (as they went out) and they also contain the sensors that I think have something to do with the brakes.
Anyway, as you learn more, please let us know.

Thanks, Ben

I called the dealer and he suggested looking at the rear wheels to make sure the parking brake is working. I just finished a 7K mile trip with the truck and towed about 6K lbs back from the lake when this happened aprox 200miles with the load.

Ben,

If you have not checked the transfer case do it now. My transfer case was bone dry when I got it to the dealer. They are having to replace the transfer case, input spline, and u-joint. I am not sure how the two lights coming on together indicated that but they said they are pretty sure that was the cause.

HOLY CRAP!!!! How do I check that?
If my transfer case is dry, I will be "P" isssssED!!!

Ben

Ben,

I have my truck back. It is running fine with no warnings. They had to replace the transfer case and fixed a couple ofother leaks. Dealer cost was $3400 for all the work done including parts and tax.