Traction Control/Stability/ABS Not working

[dorlow]

I have a 2004 Montana SV6 with a 3.5 Engine. Ok, so, a few days ago, I brought my van to Autozone because I wanted to know why the ABS, TC, Stability Control wasn't working. They checked the codes and said there was two codes for the front driver sensor which is in the wheel hub, and one code for the steering wheel. Also, the brakes were absolutely shot where they were thumping like crazy.

So, I just changed my pads and rotors. While having the pads and rotors off, I changed the front driver wheel hub.

Before changing the wheel hub, the ABS and Stability control lights came on immediately after starting the car.

Now, since changing the hub, I can drive the car for 10-20 miles. Between the time I first start the car to the 10-20 miles, everytime I stop, the car acts like I'm slipping and I can hear the ABS system working. Then after 10-20 miles, the ABS lights come on and the ABS system is disabled and the brakes work fine. But, unlike before where I only got the ABS and Stability, now it shows the ABS, stability, and TC on the dash as having a problem.

I just took the car back to Autozone to have them scan it again. I'm really doubting their logic... He scanned my car and said there are no codes. (I originally wanted them to clear all brake codes so I could have them re-alert and store again so I knew new codes and not historical ones before today.) I looked at his scan tool screen. There were no DTC codes.

I questioned if he was using the right scan tool. My OBD tool can't scan ABS. Back when I used to have a Snap On scanner, I had to have a separate ABS module to scan it. He said that isn't the case. This tool (really cheap reader he was using) can scan ABS and he was using it right. When he looked at historical codes. He found a code for the EGR valve that I replaced years ago. But nothing about the ABS they just found a few days ago. I questioned that. He said it was because the EGR valve was detected over 150 miles ago. The ABS, you just replaced it and it hasn't been 150 miles (which he called a drive cycle). That's why the EGR code from years ago is in historical but not the ABS codes. I'm really doubting his answers. Makes no sense to me.

I have a hard time believing I would've taken this car to a dealer to fix the ABS and I would've gotten the car back and the ABS light would've came on and the ABS system constantly acting like I'm on ice and they would say you need to drive it like this for 150 miles. I would've flipped out at the dealer if they told me that.

[dorlow]

Update: I replaced the ABS connector at the driver's front wheel and the ABS has worked for 2 days now. No warning lights.

[dorlow]

Oh, and I bought my own scan tool that has the ability to scan ABS and I saw the code Autozone claimed didn't exist. I erased it and so far it hasn't came back.

[Tech II]

You are correct...most code readers/scan tools, only read PCM, or "P", codes......to read ABS, you need something that can read "C", or Chassis codes.....

More often than not, these codes are set by water intrusion....when that happens, the sensor AND the pigtail to it, have to be replaced....good job on fixing your own vehicle...

[sisson_d]

Just keep in mind that the guys at Autozone are NOT mechanics. Anyone can hook up a code reader and give you the description of the code from the internet. It takes more to use this info and figure out what's really wrong and what needs replacement/repair. My guess is the second trip to Autozone, the employee used a reader w/o the ABS capabilities. A normal code reader would show no codes if they are related to the BCM, ABS, and a few other things.

Good job diagnosing and repairing yourself! But take it easy on the Autozone (or any other auto-part store) employees. I've experienced actual mechanics that make similar mistakes. That's worth getting upset about and is the reason I learned how to work on cars.