I have a 05 1500 4x4 I have installed 4.56's gears in front and rear with 35" tires every time i get on the highway and hit about 60mph my abs light and emergency brake light come on. The display screen on the dash says to have the brakes serviced soon. they will stay on until I shut the truck off and get back to about 60 mph again. I have had the computer tuned buy jesse at http://www.wait4meperformance.com/. I had another guy when I was out of town that pluged in a genises scanner and it says the code is CO245.
any suggestions on how to fix it

 

You have to have the pcm tuned with your new gear size and height of the tire's. That will take care of it. Don't just tell him 35's, make sure you actually measure them so your speedo is right also.

 

4:10's with the 35's is about as close as you are going to get. The 4:56's and 35's will never come within the tolerance of the GM computer. Your best bet is to take it to the dealer and have them tey to adjust for the gears and tires with the Tech II. I have been down this road a few times, and each time the ABS light still comes on.

there is not a tuner in the world that can make the 4:56 and 35 inch tire combo work well.....not that I know of anyhow.

 

I tuned JoehawkZ71s truck with the 4.56 gears and 35" tires.
I don't think he is getting any code problems.
Actual tire height was 34.5.
This was on a 2001 PCM if it matters.