Buick Rendezvous Traction Control gone haywire

My father owns a 2004 Buick Rendezvous FWD. He plans to replace it next spring, but for now we need it to get though winter. The problem is, the traction control turns on almost constantly. Even when he deactivates the TCS before starting, it will always turn back on at some point during his drive. It's dangerous because the TCS will brake randomly and hard, plus it grinds the brakes when it activates. The OBDII scanner said the left front hub/sensor assembly was bad. Dad has already had the front left hub sensor replaced twice, once with a PepVanceZone part and once with a better Timken part, to no avail. I'm thinking the wiring harness is loose/damaged/corroded. Any other reason TCS would be going haywire?

I did some quick googling and it seems like a common problem apparently the sensor is built into the hub and there's not enough slack and the harness gets stretched/damaged during turns.

http://www.buickforums.com/forums/showthread.php?t=13550 Post #5 seems pretty helpful but like I said I only did some quick googling.

Best of luck

Assuming (off to a bad start, I know) that there's some sort of timing/tone wheel on the hub for the sensor to read, has it been inspected for filth/damage?

Seems like an easier check than the harness, just to take care of simpler stuff first.

Apologies if that doesn't apply in this case.

RexSeven wrote: I'm thinking the wiring harness is loose/damaged/corroded. Any other reason TCS would be going haywire?

This is common. Trace the wiring from the connector back to the subframe (split the loom off), you will probably find green death within a couple inches of the connector.

In reply to ransom:

The whole hub/tone ring assembly has been replaced twice, so that's not the culprit.

In reply to lnlds and Knurled:

One or both of you sound right in this case. Mom mentioned something about the shop securing the wiring somehow, and that stopped TCS from activating until Dad hit a pothole. I've told Dad to have the shop pay close attention to the wiring the next time he brings it in. I'll mention the overextended sensor wire to him.

You might be better off with the speed sensor disconnected than intermittent. If it decides you are sliding at the wrong time, you may roll out in front of a bus when it shuts off the brakes.

But then I think you are better off without abs/traction control at all....

I don't know how the Buick will react without the sensors connected. Won't the TCS go haywire, anyway? If this wiring fix doesn't work then Dad wants the TCS and ABS deactivated, but on a modern, electronically integrated car like the Buick, I don't know if that's possible.

This is the EXACT reason I hate the tech in today's cars. You have a computer trying to do what a mechanical device CAN do. When said mechanical device wears out, it typically doesn't kill the car. If the clutches wear out, it's an open diff. When a computer or sensor goes haywire, it screws things up in this instance.
I'm inclined to suspect the computer though. Usually, if a sensor goes bad it either shorts or goes open. The computer sees this as a "out of parameter" condition and simply disables said feature. But, I wouldn't put it past automotive engineers that have never turned a wrench and are not car people to do something like this.

RexSeven wrote: I don't know how the Buick will react without the sensors connected. Won't the TCS go haywire, anyway? If this wiring fix doesn't work then Dad wants the TCS and ABS deactivated, but on a modern, electronically integrated car like the Buick, I don't know if that's possible.

The brakes will work like a normal, non electronic vehicle. There will for sure be lights lit up on the dash, and you could have cruise control and speedo issues.

+1 on that sounding pretty scary. I know of one incident where something like that resulted in the vehicle leaving the freeway backwards into a fence, and i would be surprised if it doesn't happen occasionally and no one realizes it.

Streetwiseguy wrote:

RexSeven wrote: I don't know how the Buick will react without the sensors connected. Won't the TCS go haywire, anyway? If this wiring fix doesn't work then Dad wants the TCS and ABS deactivated, but on a modern, electronically integrated car like the Buick, I don't know if that's possible.

The brakes will work like a normal, non electronic vehicle. There will for sure be lights lit up on the dash, and you could have cruise control and speedo issues.

OK. That was the one thing I was most concerned about. If the Buick's inspection date falls within the time we still need it on the road, I'll tell Dad to get it inspected if/when he can get the warning lights to go away. The car will fail safety inspection if the TCS and ABS warning lights are lit, and you can get in BIG trouble if you're caught driving a car with a failed safety inspection sticker.

I know, tear apart dash, snip the wires, but this isn't my car and I don't have the time to work on it.

Nothing as simple as pull a fuse?

my 04 Cavalier has something wrong with the ABS/TCS system. both lights are on in the dash, it likes to lock up the front wheels with minimal brake effort on pavement, and it is downright scary trying to stop it on a gravel road. teh internets has led me to believe it's something with the harness- on my car, there is a main harness plug for the front of the car right blow the battery tray where battery acid leaks on it and it's allegedly a problem area. being it's the same year as the Buick in question, that might be a place to look.

my first thought was to pull the ABS fuse to get it to act like a "normal" non ABS car- all that did was cause the "BRAKE" light in the dash to come on in addition to the ABS and TRAC lights. i'm gonna look at the harness this weekend, and if that doesn't work, i'm gonna look into ditching the ABS crap altogether and making it work like a regular old car with an adjustable prop valve on the rear brake lines.