# Brake Assist Workshop



## doublegarage (Dec 16, 2005)

Hi, 
2004 Treg V8. I keep getting a strange message at startup, I've searched the manual and this site but no luck yet. 
The car starts, there's a loud beep and in the instrument binnacle display I get "Brake Assist Workshop" with a large picture of the car heading down a steep slope - this then goes away leaving a mini-icon of the car descending a hill at the top of the display - next to where the re-fuel icon appears...and...the ABS light and the system warning light stay on until the next time the car is re-started. 
A re-start causes it to be instantly cleared, both the brake-assist display and the ABS and warning lamps.
Seems to be related to whether I keep my foot on the brake as I start and warm up the car - which I have a habit of doing. 
Probably just spaced it finding this in the manual but it's kinda annoying - any help appreciated. 
Thanks, 
Richard 
San Jose


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## SSP (Feb 9, 2005)

*Re: Brake Assist Workshop (doublegarage)*

Stepper motor problem
http://forums.clubtouareg.com/...ymbol 
Final Count, parts changed:
0AD-341-601-C Motor positioning motor
0AD-927-755-AB Contr Unit transfer box control unit
0AC-927-771-C Contr Unit control unit for axle differential lock
0AB-341-601 Motor positioning motor
0AB-501-649 Seal round seal 
Stepper Motors (twice)
0AD-341-601-C Motor
SSP.



_Modified by SSP at 3:33 PM 12-16-2005_


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## TREGinginCO (Jan 4, 2004)

*Re: Brake Assist Workshop (SSP)*

This one sounds a little different. I wonder if there is an ABS sensor that has gone bad. Another thought... check your brake fluid level.


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## SSP (Feb 9, 2005)

*Re: Brake Assist Workshop (TREGinginCO)*


_Quote, originally posted by *TREGinginCO* »_This one sounds a little different. I wonder if there is an ABS sensor that has gone bad. Another thought... check your brake fluid level.

Actually , this is EXACTLY word for word what I faced. The link I gave is the whole saga on my 04 V6's stepper motor problems, incl pictures of warnings he is describing
SSP.


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## doublegarage (Dec 16, 2005)

*Re: Brake Assist Workshop (SSP)*

Thanks SSP - sounds like exactly the fault - right down to the happening 40% of the time I startup. 
Just so that I can talk intelligently when I take this to the dealer - what is this "stepper motor"? I think of stepper motors as little actuators for opening, for instance, ventilation flaps in increments...this must be something more powerful? Is it actually the solenoid that locks the rear diff? Or something to do with applying the brakes in a controlled descent?
Thanks for any info
-Richard


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## 4x4s (Dec 18, 2003)

*Re: Brake Assist Workshop (doublegarage)*

The infamous stepper motor is used to actuate the center differential lock, as needed by the demands of your driving. There is another stepper motor used for the same purpose for the rear differential, if your Touareg is so equipped, but most references to the stapper motor you read about on this forum refers to the on for the center diff.
It is very much like the actuator you liken it to, and very much more than a simple solenoid. No direct relationship to braking, though the control units may very well choose to adjust the center diff locking (via the stepper motor) in response to braking if conditions warrant it.


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## SSP (Feb 9, 2005)

I havent heard of anyone else get the 'downhill symbol' along with the stepper motor problem. Thats why you mentioned that I knew you were facing the same problem.
Usually people feel the 'jump' and the binding while taking a tight turn. I didnt feel the jump at all, just a little binding, which I realized after they put a new stepper motor and I saw the difference.
Hopefully your service dept will work with you to get this resolved as soon as possible. Mine took over 5 visits but finally they got rid of it.
Good Luck!
SSP.


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## doublegarage (Dec 16, 2005)

*Re: stepper motor*

update on this for anybody interested....
I took the car in for the 20k service and listed the Brake Workshop as a warranty fault. 
First they said it was a bad battery and replaced it - something about "load faults showing up".
But then they test drove it again and the fault came back - said they were going to replace the alternator wiring harness. 
Then decided that it had a stepper-motor problem because they could feel the shuddering during tight/slow turns (have to confess I hadn't noticed but then I've never had an SUV before so I was probably blaming it on something else)
So they replaced the rear diff-lock stepper motor..
and so after 13 days I have the car back - no sign of the Brake Descent Workshop warning yet...
Thanks for all help above, very useful when discussing with the service guys. 
-Richard
San Jose, CA


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