I have a 2001 Audi TT Roadster Quattro 225HP Turbo (AWD). A few months ago I took it for an alignment at a tire shop and right after that my ESP light would flash every time I would make a sharp turn or a "not so sharp turn" on a road in level (i.e. making a turn when leaving the drive-way to get on the street) and the car loses power, losing traction.

I thought it would be the steering angle sensor (got disconfigured because of the alignment), so I used my Ross-tech VCDS to zero it. It helped a little, but the problem didn't really get solved. I took the car back to the shop and they realigned it. Still didn't solve the problem. After the realignment, I zeroed the steering angle sensor once again and no luck.

The procedure I use to zero the steering angle sensor can be found at: http://www.ross-tech.com/vag-com/car...ringangle.html.

In summary, whenever I make a sharp turn, a 360, or I am leaving my driveway and turning on the street (uneven pavement), or I'm backing up and making a sharp turn while leaving a narrow parking spot, the steering angle sensor light starts flashing and I can clearly feel that incorrect traction is being sent to the wheels. The car starts to bog down (kinda having some hiccups), losing traction on the wheels, and slows down considerably (feels like major misfires, losing power - but it is clearly a traction issue).

I also ran a full scan using my RossTech VAGCOM and no error codes were found related to the module(s) that may possibly control the traction (as per my understanding): ESP, HVAC, Haldex, and ABS.

So, the question is: HOW DO I FIX IT? The car was running fine before the alignment. I never had this problem before. And I can't fix it by just calibrating the steering angle sensor using the rosstech procedure cited above. It always helps, but never solves the problem for good.

THANK YOU SO MUCH in advance!!!

 

Only error code identified by my RossTech VAGCOM (VCDS), but this error code is there way before I started having this problem:

Address 45: Inter. Monitor Labels: 8E0-951-177.lbl
Part No: 8N7 951 177
Component: Innenraumueberw. D14
Coding: 00001
Shop #: WSC 00000
VCID: FBFB82D2C397

1 Fault Found:
65535 - Internal Control Module Memory Error
00-00 - -

 

LOL dude... that is your traction control. If you are turning sharp, your wheels are not maintaining the same speed and your traction control will try to adjust.

It will happen when you try to turn sharp and fast... solution? TURN IT OFF via the little ESP button on your console!

 

Well, I wish it would be that simple. :-)

I'm not turning sharp and fast, I'm making a regular u-turn at normal speed. In fact, the problem happens only at low speeds.

As I said, this problem didn't occur before the car alignment, and my driving style didn't change either.

Any other thoughts?

 

Does that sound like your problem? Does it sometimes chirp the inside rear tire as it does this? If so, suspect the Haldex controller. There have been a couple of QuattroWorld posters who reported this problem and had to replace the Haldex controler to correct it.

Do what applies (roll out test, and jackstand/lift test)

Function-test of the Haldex coupling.

- Rollout in circle

Aim: Check the function of the coupling and the response on the car. Is to be done on level ground.

1. Drive in circle with minimum turning radius at a speed of about 10 km/h.
Disengage the clutch and close the throttle.
Let the car roll to full stop.

2. Drive in circle with minimum turning radius at same speed as in case 1.
Disengage the clutch and run up the engine to 3000 - 4000 rpm.
Let the car roll to full stop.

* If the coupling is working the car will stop in about half the distance in case 2 compared with case 1.

* If there is no difference in the two cases there is a malfunction of the coupling. The problem could be caused by the coupling or by missing signals from the car. A further inspection has to be done to be able to determine the cause of the malfunction.

* If a noise from the HLSC is noticed when turning or driving in circles the oil in the coupling is damaged. The damage can be caused by overheating or by water in the oil.


- AWD test on car lift. (all wheels free to turn.)

Aim: Check the function and the control of the coupling.

1. Pull the handbrake.
Disengage the clutch.
Start the engine.
Put the gearbox in 2:nd gear.
Let the engine idle.
Engage the clutch.

* Engine is supposed to stop when the clutch is engaged. (HLSC controlled as in handbrake start.) If engine do not stop, disengage the hand brake immediately. Otherwise there is a risk of seriously damage on the HLSC.

2. Disengage the handbrake.
Disengage the clutch and start the engine
Put the gearbox in 2:nd gear.
Let the engine idle.
Engage the clutch. At least one front wheel and one rear wheel is supposed to turn.
Pull the handbrake for 2 seconds.

* Front wheel is supposed to turn while the rear wheels are supposed to stop when the brake is pulled. Engine is supposed to run all the time. (HLSC controlled as in handbrake turn.) Don't exceed the 2 seconds or repeat the test for more than 5 times during a 5-minute period. Otherwise there is a risk of seriously damage on the HLSC.


Trouble shooting on HLSC

- Visual inspection

Aim: Check for leakage and external damage that affects the function on the HLSC. Is to be done with the car on a car lift.

1. Check for oil-leakage from the coupling. If leakage is found, check oil level at the level screw on the left side of the coupling.


2. Check wires and connecting sockets.

T8 - Socket between car and control unit
T8/1, Red = Ign.
T8/2, Black = Gnd.
T8/3, White = BLS
T8/4, Blue = HBLS
T8/5, Brown = K-line
T8/7, Blue/Grey = CAN low
T8/8, Blue/Orange = CAN high

T2 - Socket between control unit and feeder pump
T2/1, Yellow = Pump 1
T2/2, Yellow/Black = Pump 2


- Signals

Aim: The following signals from the car affect the function of the HLSC. If one or more of the signals is missing or false the function of the HLSC will be reduced.

Bremse 1; BLS, BTS, ABS
Bremse 3; VR, VL, HR, HL

 

Will do and will let you know the results over the weekend. THANK YOU!!!

 

My lateral acceleration sensor is bad and my car does alot of the same stuff... try resetting that?

 

Thanks for letting me know. I will check on it.

In fact, I found a nice page from RossTech showing the steps to reset the brake electronics. Here it is:

http://wiki.ross-tech.com/wiki/index...#Basic_Setting

I will test it out tomorrow,

William.

 

(Suggestion are really welcome!) This is what I tried so far (and no luck):

1. Disconnect the battery cables, touch them for 15 minutes, reconnect the positive, turn the key on, connect the negative and finally drive straight until all the lights go off AND... unfortuantely it didn't work. Actually, it got worse. Now, when I'm making a u-turn or 360, the car starts struggling even before the ESP lights starts flashing.

2. Reset and check the values for the following sensors: Steering angle sensor, Lateral Acceleration sensor, Brake pressure sensor, Longitudinal Acceleration sensor. But still, the problem is the same.

3. Now, a few important things that I noticed:
3.1. The problem is not just in one wheel, it is apparently on both rear wheels (front wheels are OK). I'm saying it because I was doing 360s at aprox. 10mph and the rear left wheel when I was turning counter-clockwise or the rear right wheel when I was turning clockwise would start "receiving" more power torque than to others, which would make it to spin in false (spin more than the other wheels).
3.2. The measured values for all the sensors mentioned above are OK, well within the specifications range.
3.3. Since it is an AWD with haldex clutch, the problem really seems to be there! The haldex clutch or the AWD may not be working properly so it allows more power to one of the rear wheels when making low-radius curves.
3.4. When I turn off the ESP control using the button in the console, the problem still persists, so that kinds of eliminate a possible ESP problem, correct?
3.5. When I drove the car in a circle, but driving backwards (rear gear), the ESP light didn't come on at all, but the rear wheels were still spinning in false (more torque than required).

4. I tested the haldex coupling using the procedures suggest by J. Paterson and in procedure 2 (accelerating) the car stopped much faster, which means that the haldex coupling is fine. Is there a way that I could test the haldex controller with my VAGCOM to make sure it works?

5. I will test the AWD tomorrow, since I will have to take the car to a shop to put it on a lift.

Again, suggestions are really welcome and appreciated. Thanks guys!

 

Another very important detail:

When I replaced the Haldex oil and filter, I purchased the oil and filter at the dealer, but the service was done in another shop (which I trust, but you never know).

So, the question is: Would it be possible that air was trapped inside the haldex compartment while replacing the oil and, for that reason the haldex is failing?

I did a visual inspection now and there are no leaks, the filter is tight, and I didn't see anything that could turn into a red flag.

Thanks for all the support in advance!