# Pulled Fuse 31 (BINDING PROBLEM!!!)



## Richym13 (Feb 2, 2016)

Hey guys so I got a 2002 AMU Audi TT 225 Quattro with around 180k miles...

The only mod done to it is I have upgraded to a 3 inch downpipe and deleted the cat and muffler. 

It does have some boost leaks but to this point I have not tackled them down will do in the near future though.

WHAT I DO NEED TO TACKLE IS THIS PROBLEM THOUGH SO...

Unfortunately on tight turns car starts binding. Did a small amount of research and from the knowledge acquired it all seems to point to the Haldex mechanism.

So my research led me to pulling fuse 31. Surprisingly that alleviated my binding problem. The traction control light did go on in my dash though. Car does feel a little lighter to me and shifts feel more notchy to me.


Next I will service the haldex. I have the service kit for the haldex filter/fluid. 

Will also check the earth strap. In many cases it seems to be the culprit. 

Once this is done I will put back fuse 31 in its place and see how the car performs. Hopefully binding problem goes away. 

Will also raise the car and check if all four wheels turn.

Now...

Has anybody here gone through this? 

What have you performed to your car that alleviated binding problem?

Is there any other thing I can possibly check or perform on the car?

Have you guys performed a differential replacement? is it hard?


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## lite1979 (Sep 9, 2005)

I'm in the same boat. If I leave that fuse in, I have all-wheel-drive, but it's binding in low speed turns. If I pull the fuse, only front-wheel-drive.

I suspect a valve in the Haldex unit is constantly allowing the clutch disks to engage, hence the 100% rear wheel torque at low speeds. In normal operation, I think this valve is supposed to operate differently, allowing easy turning at low speeds. 

My plan is to find another haldex and differential unit that I can take apart, or replace mine with a known working unit and figure out how to fix my current haldex.

Unfortunately, I never drive, and my TT is on jackstands until I give the wife a new bathroom...

Sent from my XT1254 using Tapatalk


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## Richym13 (Feb 2, 2016)

So you are just going to replace the whole unit and then work on yours? even though you do not use your car?

I feel you man lol gotta keep the queen happy!!

I daily my car every day to my job. It is only like a 10 min drive or less. 

I really want to enjoy the car in canyon runs but this specific problem has been keeping me away.


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## lite1979 (Sep 9, 2005)

I haven't done it before. That's why I want to get a second unit first. I need my garage for my truck and the wife's car, among other projects..

Sent from my XT1254 using Tapatalk


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## Richym13 (Feb 2, 2016)

lite1979 said:


> I haven't done it before. That's why I want to get a second unit first. I need my garage for my truck and the wife's car, among other projects..
> 
> Sent from my XT1254 using Tapatalk


Well hopefully it works out for you once you find it. 

I kind of want to look for the specific problem before I go that route. 

Is there any negative effect leaving fuse 31 unplugged for long period of time?


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## lite1979 (Sep 9, 2005)

None at all, unless you count no traction control as a problem. 

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## Richym13 (Feb 2, 2016)

lite1979 said:


> None at all, unless you count no traction control as a problem.
> 
> Sent from my XT1254 using Tapatalk


Not really no unless spiritually driving. My trip to work doesnt really require it lol


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## bwdz (Jan 21, 2015)

I've had this problem and explained in several threads that you might fix it for next to nothing. It is the stepper motor inside the controller that locked up on mine but freeing up the motor from it's stuck spot seem to make it work again.


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## lite1979 (Sep 9, 2005)

@bwdz: so the stepper motor acts as a valve, right? If that's the case, I'll volunteer to take pictures as I take mine apart and make a DIY thread.

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## J Patterson (Apr 11, 2009)

I have not had this problem but over the years several have reported correcting it by replacing the Haldex controller. And yes I remember the stepper motor being the failure point.


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## Richym13 (Feb 2, 2016)

And this is why I love forums!!!!!! :heart:

Dam a diy thread would be great!!! 

If I find some time I will definitely do some more researching on what you just explained bwdz...


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## MCPaudiTT (Nov 26, 2006)

Not a DIY, but I did dissect a controller down to the bits and pieces.

http://public.fotki.com/mcphill/audi_stuff/engine_and_drivetrain/haldex-autopsy/


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## Richym13 (Feb 2, 2016)

MCPaudiTT said:


> Not a DIY, but I did dissect a controller down to the bits and pieces.
> 
> http://public.fotki.com/mcphill/audi_stuff/engine_and_drivetrain/haldex-autopsy/


Steps 8-11 are exactly what bwdz is trying to explain...

This write up alone is great with all the pics and descriptions. Above all now I feel really confident this might be the issue for binding plus it seems something not that hard of tackling. 

Were you able to free up the stepper motor? or were you able to order one?


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## bwdz (Jan 21, 2015)

lite1979 said:


> @bwdz: so the stepper motor acts as a valve, right? If that's the case, I'll volunteer to take pictures as I take mine apart and make a DIY thread.
> 
> Sent from my XT1254 using Tapatalk


 The stepper motor moves the valve. There was some corrosion on the outside of my Haldex but none on the inside. The stepper motor would not turn and the valve was stuck in one position. Putting a pair of pliers on it moved it and then it seemed to free it up. I had a replacement controller that I already put on so I never put the one I dissected back in so I don't know if it will actually fix it. I speculate that you don't even need to open the controller, I feel like once you take the controller down you could potentially just gently try pushing on the valve through one of the holes and see if you can just get it to budge. I would not use a anything that can gouge it too bad but a pick should get in there. Don't forget to order the metal crush gasket whenever you will take the controller out. VW and Audi will tell you it doesn't exist so you have to google the part # and then your local dealer can order it for you. There is not a lot of room up there and I did one time install the controller and the gasket must have slipped on me and it made a bit of a mess, luckily I still had it up on the hoist to test so I just ran it for a second and saw the fluid dripping. Since it is only 2 bolts and a $11 gasket plus a little fluid it sure seems worth trying.


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## Setflyn41 (May 10, 2017)

The earth strap can cause this? 
Same issue here I am getting ready to buy a controller but when I replaced the fluid I noticed the earth strap was broken, but didnt really think that could cause that big of an issue


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## Gonzalo1495 (Feb 2, 2015)

I had a similar issue recently. I had insane binding at low speeds and turning (parking garages were the worst). Turns out the Haldex was low on fluid because of a leak. Fixed it and no more binding. Hopefully that's your culprit


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## MCPaudiTT (Nov 26, 2006)

Richym13 said:


> Were you able to free up the stepper motor? or were you able to order one?


This unit was a donated "dead" one that I was just interested in taking apart. The ones in my two TT's work fine, so I have had no need to try to fix the stepper. I was not able to quickly find a known cross-reference number, though, so it likely isn't super simple to find a like-for-like spare other that off another (wrecked) TT, in which case you might as well just swap the whole controller over. As stated in the photos, I do think I had freed up the motor on the one in that unit and felt it likely would have worked, but who knows how long it would have lasted.

I should add, too, that I don't think the stepper rotates very much at all for the full travel over its life, which may contribute to "wearing out" one area of the motor. It would probably be best to mark the pinion gear alignment to the motor and ensure to install it 180 degrees opposite, that way you are hopefully working a different area of the armature, bearings, etc than were originally involved since it was installed in the car at Audi...


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## Richym13 (Feb 2, 2016)

Setflyn41 said:


> The earth strap can cause this?
> Same issue here I am getting ready to buy a controller but when I replaced the fluid I noticed the earth strap was broken, but didnt really think that could cause that big of an issue


When I did my research a lot of threads came up and I went through them and yes I came across one post stating that can also be a cause...

Hopefully replacing your controller gets rid of the binding let us know!!!


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## Richym13 (Feb 2, 2016)

Gonzalo1495 said:


> I had a similar issue recently. I had insane binding at low speeds and turning (parking garages were the worst). Turns out the Haldex was low on fluid because of a leak. Fixed it and no more binding. Hopefully that's your culprit


Yes really hoping it is that once I do the service!!! Where was your leak??


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## Arizman3 (May 30, 2006)

well, how exactly did you solve the low speed binding problem? I have the problem on my '02. Did you replace the controller? what? 

Thanks


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