ABS Locked my car up in the middle of nowhere...

[ditchbum]

When it happens again, I'll try to get a vcds reading while its "frozen", hopefully when the lights are on (ABS/ESP...). Just means I'll have to travel with the computer... Have not done anything to the axles as the car drives very well at freeway speeds (80 mph+ ) no vibration at all. For what its worth, the problem has seemingly only occurred on the very curvy road I travel to go to work ( twice...) and once on the freeway with poor quality pavement.

 

[ditchbum]

Also I forgot, I'll try to see if the car moves/drives upon the next occurrence if ESP button is depressed...

 

[ZippyNH]

..... Are there components involved with that system that go bad?

Wheel speed sensors.... steering Angle sensors....

 

[PickleRick]

Can you bring a jack? Raise the vehicle if it locks down again to see which wheel (s) are dragging! Might also be able to use a remote temp sensor but if it's a mountain pass that might skews results depending on on how spirited the driving is

 

[ditchbum]

Steering angle sensor....hmmm....also called an airbag clockspring.... hmmm... my last scan showed airbag fault code, 00532, supply voltage to low- intermittent...anybody think this could be a cause of my issue? Sending a signal to my ABS to shut the car down? Looks like that sensor isn't the easiest thing to replace... also think I read somewhere I should try to clean it with some magic fluid...Thoughts anyone....?

 

[P2B]

Which module(s) reported low battery voltage?

 

[MEgearhead]

I'd drive it on the same route that has caused issues before a few times with ESP off and see what happens. If it doesn't happen when ESP is off then you have narrowed it to the ABS/ESP system.

The reason I asked about axles/CVs is the reluctor ring for the front wheel speed sensors is part of the outer CV. I have had issues with some aftermarket CVs causing the ABS/ESP to freak out.

The clockspring might also be the issue.

I'd try to narrow it down a little further before I started replacing this, but that's just me.

It would be pretty easy to crack a bleeder briefly on each caliper when the brakes are locked up. You can also crack the lines at the ABS unit.

 

[PickleRick]

By expanding a search to all b5 and b5.5 models rather than focusing on the TDI models that exactly code and random brakes locking down appeared on I believe Passat world on maybe a 1.8t. He found a short in the abs control module. I've never been into the abs on the Passat but in the disco 2 this is located in the belly of the abs unit. While they don't lock down the disco 2, you can remove them to see wire insulation that are falling apart due to age causing a short and $$$$ Passat module failures are well documented over the years.

Perhaps you can simply unplug the abs. This will disable the abs, she'll brake like a 1975 family sedan.

This will allow you to at least take abs out of the equation, the electronic control part of if anyway.

 

[2004LB7]

What about something as simple as moisture in the brake fluid? Boiling when warm causing pressure in the caliper. Then a few minutes with the engine off it cools enough to release the brakes

What about trying to bleed/flush the fluid?

 

[ditchbum]

Sorry, took a tryptophan break... Appreciate all the suggestions and will try each, starting with turning the esp off. Definitely not looking to swap the clockspring, but it looks doable if necessary... Also saw an ABS module rebuild service on the flea, also reasonable as opposed to replacement. As this car has a porsche front caliper "upgrade" , I'll check the sensors and stuff there first . Really like this car when its rockin'...

 

[caffeine]

I don't see how it would be possible for a clockspring to cause this issue. The only thing the clockspring has to do with the ABS/ESP system is the steering angle sensor. It would be faulty programming if any input from the steering angle sensor could cause the brakes to lockup.

 

[ditchbum]

steering angle sensor. if faulty, might send a signal to ABS to brake. Not sure what other faulty programming there is other than the steering angle sensor. If it is faulty , gotta remove the clockspring don't I?

 

[caffeine]

steering angle sensor. if faulty, might send a signal to ABS to brake. Not sure what other faulty programming there is other than the steering angle sensor. If it is faulty , gotta remove the clockspring don't I?

What I meant was, in what universe would it be rational to program the ABS module to *lock any of the brakes* in response to steering angle input. Yes the ESP can apply brake pressure, based in part on steering angle input combined with other sensor data, but it should never be enough to cause the vehicle to come to a complete stop. When the ESP system applies the brakes, it's usually just one or two at a time, lightly, to aid with cornering dynamics or assist traction.

 

[ditchbum]

Completely agree. It shouldn't lock up my brakes. But something IS. It just seems like a plausible possibilty if the steering angle sensor has a short or some other electrical issue that sends a signal to the ABS to brake (seemingly all 4 wheels, though have not confirmed it ) and doesn't "undo" that signal until the car is shut off. Have resorted to driving it with the laptop close by to scan on the next occurence. We'll see what happens then....

 

[ZippyNH]

Honestly if I had to bet $$ I would guess the abs computer is dying.it should turn off, light a light....
So it's a hard failure or getting data till you cycle the switch.
Esp is typically just a function of the abs in most makes, it adds a gyro typically, looks at the steering wheel angle sensor and the path of the car..
Then depending on it can activate individual brakes to tighten a turn, etc
Kinda complicates things when other items are bad...it's why some shops won't work on older cars...if the clock spring is bad..which is not a steering angle sensors on most makes, but could be integrated in some(honestly don't know on a VW)...hell could it be sending info saying airbag deployment? Then as a safety feature the brakes lock up? Just spit balling cause this is definitely an odd case.
Know when my car got hit, the Porsche mechan deployed its airbags as it hit me then rolled a few feet then brakes locked up, shut off as I was spinning around,
Dashcam vid was priceless, showed the insurance company he was 100% at fault.

 

[P2B]

Honestly if I had to bet $$ I would guess the abs computer is dying.it should turn off, light a light....

I concur. A properly functioning ABS module can pulse the brakes in response to various inputs, but it should never lock them under any circumstance.

 

[caffeine]

Completely agree. It shouldn't lock up my brakes. But something IS. It just seems like a plausible possibilty if the steering angle sensor has a short or some other electrical issue that sends a signal to the ABS to brake (seemingly all 4 wheels, though have not confirmed it ) and doesn't "undo" that signal until the car is shut off. Have resorted to driving it with the laptop close by to scan on the next occurence. We'll see what happens then....

Off the top of my head, the only wiring between the clockspring and the ABS module is a serial data line, so again, no faulty signal from the clockspring should be able to cause the brakes to lock.

 

[MEgearhead]

Throw a 10mm or 11mm wrench in and simply crack a bleeder on each caliper, if it does it again. Or, a 12mm (I think), and crack the fittings on each of the brake lines going to the wheels at the ABS unit briefly. If the problem is in the hydraulic system brake fluid will come out under pressure, and once relieved, the brakes will no longer be locked up. Simply crack them open and tighten them back one at a time. With the pressure relieved you can then go on your merry way (until it happens again) with the issue at least narrowed down to the hydraulic system, or ruled out. You'll want to check the wrench sizes ahead of time.

 

[ninedee_golf_tdi]

I once had a vehicle that had water in the brake lines. The water froze and expanded locking up the brakes. Just my 2 cents.