frocco

Hi, I'm looking for a little input on a problem with my 02 TT Quattro.
I just purchased it with 135k miles. When I got it home I noticed that when I was backing up with my wheels turned almost all the way the back wheels were grabbing and slipping like a full time 4x4 truck. Never having a Audi/quattro vehicle I did some research and can give the following details.
I did the turning circle tests and had the following results.
When in a slow circle with the clutch engaged the back wheels tugged, slipped like the haldex was engaged. I disengaged the clutch with no throttle and I rolled to a stop, no more tugging. Did the same except ran the engine to 3000rpm after disengaging the clutch. in this case it rolled to a stop much slower. I then had it on a lift, I did test 1 by letting out the clutch with the Ebrake engages. the engine stopped. Test 2 failed which was letting out the cluch and then pull the Ebrake. In this case the car stalled also.I believe that the controller was supposed to disengage the haldex on the Ebrake signal but did not. If I unplug fuse 31 for the haldex controller the haldex disengages and I am in 2wd.
With the shareware vag-com software I was able to log into log into the Haldex controller and see no codes so it appeares that the controller has communication. Also the ABS controller shows no codes and comunicates.
I believe that I might have a bad Haldex controller hoping someone might have some insight on a way to verify it or what else might be wrong. If the AWD was not working i would understand but the fact that the controller is engaging it on purpose bothers me.

frocco

Just for an update, I put a haldex controller in that I purchased from ebay in($99). The result is that it is no longer locked in AWD but when I scaned the Haldex controler with vagcom
it shows the following fault - 65535 - Internal Control Module Memory Error
Sounds like this controller has other issues. At this time I do not know if AWD is working or not. Only had time for a short test drive. I will put it on a lift after the weekend and check. The good news is that before I saw the controller on ebay I purchased a whole diff assembley with haldex and controller from a JY for only $200, so when that one comes, I'll have a third to try!

willieC

I am having problems with my haldex aswell, I don't know much about them but it sounds the same problem as I am experiencing. If you get any information please pass it on

frocco

As I said above, my initial problem stopped after swapping out the Haldex controller. I have not fully verified that awd works but it seems to be, I cannot get the wheels to break free. I do have another controller but I will not be able to try it until after the winter. So I believe my issue was caused by a bad controller and my advice to you is the following based on my experience and all that I have read from these forums.
If the Haldex oil and filter has not been changed lately, do it.
Keep an eye on eBay and/or JY
For a controller. It is not that hard to change out and might be cheaper than a trip to the dealer just for them to diagnose the problem.