2002 AWD and Brake issues.

[Bauer30]

Hello everyone, i got my bravada few months ago, when we didnt had snow at all. For the last few days we got some snow here in toronto and for my surprise my AWD is not working at all. Like few other users described here i have no lights on my dashboard, no noises, nothing to show that i have a problem with my AWD until you really need it to work. The car drives just fine, but when i get into some snow the rear wheels spin and i have hard time to get out there. Front wheels never get traction no matter how much i spin the back wheels. My tires are not brand new, but they are not bad at all. Im also having problems with my brakes, it works fine when im going up to 20km/h. But when i use it at very low speed, like 10km/h or less, few seconds before complete stop it makes some noise and the brake pedal shakes like the abs is working even on dry surfaces. This problem gives me a message, service brake system. Right now im a bit worried about it because thats the 2 things (ABS and AWD) we need most when winter comes. Im going to check it with my mechanic soon, but i would like to share it here and hear from you guys if anyone have had similar problems and how much it cost to repair. Thanks everyone.

[Chris Stewart]

Sorry you're having AWD trouble when you need a functional AWD the most.
I agree with you taking it to the shop because if there's no codes and no other symptoms, it's hard to even take a guess.
Just to be sure you have a functioning Check Engine or AWD light, do they come on for a second after you first turn the keyswitch on?

[Bauer30]

Thanks for your reply. Yeah, all my lights turn on for few seconds when i start my car, check engine, abs, air bags, awd etc... then they all go off. Im going to check the ATC fuse under the hood today to see if it is okay. I will keep posting news here. Thanks everybody.

[Bauer30]

After some good hours reading around i think i have some idea about whats going on with my car. I Checked the fuses and they were all good. I Pulled my ABS fuse out and went for a test drive and the problem on my brakes just went away, but as soon i put the abs fuse back the problem comes back. My mechanic got the codes from my brakes message and it he said my speed sensors in one wheel is bad. Reading around the web i found out that those sensors are used to sense the difference in wheel speed to activate the SmartTrack system. If there is an ABS fault the AWD (SmartTrack) system will not operate. Anyone knows if that is true??

[Chris Stewart]

Sounds good, the AWD depends on a signal from the front wheels and back wheels to determine if there is need to engage the AWD. There is a speed sensor on each front wheel hub and one at the transmission... does your speedometer work?
Did he say which speed sensor or what the code was?
I've read that some sensors pick up enough metal filings to cancel the signal and simply cleaning the filings off clears the problem.
I had to replace the passenger side front hub on my '97 Bravada and the new hub came with a new wheel speed sensor. The wire & insulation broke on the new sensor in less than a year but I'd kept the old hub as spare and replaced the new speed sensor with the old to fix mine.

I simply followed the wire that runs off the front of the frame and runs to each wheel to locate the break.

Evidently the aftermarket doesn't check the durability of their stuff.

[Bauer30]

I dont have the codes, he just told me it is the sensor on my right front wheel. Yeah, right now my speedometer works, but i remenber when i went to test drive my car before buy it, the speedometer was broke and i asked then to fix. Sounds like after i fix my brakes my awd will be fine, i hope soo Thanks for your information.