Have you consistently changed the brake fluid since you have owned it? Brake fluid in todays modern vehicles needs to be changed every 30k miles as preventative maintenance. I have the same thing going on right now in my vehicle. Here are the options. It could be:
A. Bad rear wheel speed sensor in the rear differential (if applicable.) <-- Cheapest fix
B. Bad ABS speed sensor on one of the four calipers (if applicable)<-- cheap-ish fix
C. Bad ABS controle module (doubt it, but possible.) <-- take a valium and hold on
D. Bad brake fluid level sensor. <-- could be several hundred to 1000 dollars to fix depending on system.
Brake fluid is hydroscopic and binds with water and will eventually, if not changed, corrode the electrical components of your ABS and braking system. When this occurs, it can be boo-coo money to fix.
Here is my suggestion, read up on your vehicle on one of the many chevy forums and find other people that have experienced the same problem. Then go to your local Harbor Freight and purchase the $120 scanner that does check engine lights, ABS, transmission codes and SRS codes. Outstanding scanner for the price, considering that if you took your vehicle to a mechanic, the would charge $100 to scan the same thing. Then use the information from the scanner, coupled with your research to diagnose the problem and correct it. The good news is that ABS is not mandatory and that your vehicle will still operate while you are fixing it and/or waiting to allocate the funds necessary to fix it.
Use the 20% coupon code and get your free gift at the same time
Had the same thing happen in stages to my BMW. Oh and the speedometer would only work intermittently for extra entertainment.
I had the ABS module rebuilt for about $300 US. It has a 5 year warranty too. It all works fine now. It took less than 5 minutes to take it out and 5 minutes to put it back in.
You can Google "ABS module rebuild" for details.
Maybe you can pay a local mechanic to pull the ABS codes. The code readers that Autozone uses might not be able to test for ABS and traction control errors.
Typically a speed sensor has failed, but a variety of things can happen to cause the problems you encountered.
I'm not sure how 4WD/AWD works on your car, but in some vehicles, the transfer case sends extra power to the front wheels when low traction happens. I sure hope that you aren't having transfer case problems.