2008 GMC Brake Issues

[trapper]

I am having a problem with my truck and am looking for help if possibe. The problem I have is the truck develops a problem shortly after driving it. The dash says service trailer brakes and the brake light and ABS indicators light up as well. The big issue is as soon as it does I have no trailer brakes. The truck does not have any codes when I scan it. I believe a better code reader may see it and I am going to borrow one and see if it does. I have checked all the wiring and cannot see any problems anywhere. I just recently did the EFI live update to a tow tune but i don't think that is the problem. As soon as I stop the truck and turn off the key the light goes away but comes back shortly after driving it again. Any help or ideas are appreciated.

 

[VHR]

Check your pulses per mile, H0101 in the speedometer section of the tune and make sure they aren't wacko. Very easy to overlook especially when running a script. Guess how I know.

 

[trapper]

H0101 is not listed in my tune?

 

[RKTMech]

There have been some issues with GM's built in trailer brake hardware and wiring. I dont think it will be an EFI live caused problem

 

[VHR]

I missed the year of your truck originally. Yes there is no H0101 in LMM tunes. In that case I would check H0136, revolutions per mile.

 

[bullfrogjohnson]

I also think there was an issue with the plug at the rear of the vehicle. Make sure there is no corrosion or rust built up inside.

I do remeber this being a problem when the 08 first came out, I belive there is a couple threads on it somewhere on here.

 

[bullfrogjohnson]

Could be this. Check the codes and get back to us.

http://www.duramaxdiesels.com/forum/showthread.php?t=8747&highlight=trailer+brake