97urS6

I discovered that my steering rack was leaking fluid about a week ago. Ordered a used rack from Wolf Auto. It arrived and my mechanic installed it yesterday. I reviewed many posts on this forum to get details on performing that procedure (thanks to all that contributed their experiences).

Today, they sent the car in for a four wheel alignment... and apparently they got that done... but it take quite a long time? But when I got the car back, the ESP was not working very well, as it engaging even while I drove the car straight ahead? The ESP light flashed on and off until eventually the center info panel on the cluster displayed "ESP Fault Found" and ESP disengaged completely (ESP light stayed on solid)... then the car drove normally.

So I hooked up my VCDS can found tons of fault codes... on almost every system? Many of them were "exceeded lower voltage limit"... so I assumed that the mechanic may have let the battery go too low? So I cleared all of the codes and put the battery on charge. Noticed the battery to be reading 12.2 volts, but it was accepting quite a bit of amps, so it was quite low! Most of the codes did not come back (whew)... but one that did come back was in the ABS module 03:

00778 - Steering Angle Sensor (G85)
Implausible Signal - Intermittent

Any ideas on where is this sensor is located? Is it possible that it is part of the used steering rack and came as a faulty sensor or is it a separate part?

MP4.2+6.0

Yes any time battery is run down you get those voltage codes all over the modules. Just clear and the see in due course battery seems fine starting wise and such.

Meantime, hope they didn't screw up the sensor bottom line. It is directly behind the steering wheel. It is integrated with what is called the clock spring in the vernacular--what interconnects all the steering wheel switches, the horn signals and the airbag down into the steering column. So, bottom line if it is screwed up, the mechanic's fingerprints are basically on it. Part is several hundred $, dealer only and can't be reused absent special care in how you keep it located. New ones come with what looks like a grenade or fire extinguisher pin that comes out as you push part home. On the other hand column shouldn't need to come out of wheel off for rack--at least for my Audi 5000 nightmare of a job from the early 90's--so I can't be sure. You can pull steering wheel and move it on the spline too if in final work the wheel was not correctly centered so it shouldn't have happened even if that was done; BTDT.

There are various connectors on the clock spring + sensor unit. Could be some of those are slightly loose/not pushed down firmly. I had that issue a couple of times with my driver's airbag that would kick a code (and dash light) for an intermittent signal issue. The ESP fault probably ties to this sensor too since it relies on it to know how driver is steering. Sometimes a dash light/warning comes on specific to that sensor; also used for adaptive headlights if you have them. I would get this same error sometimes disconnecting battery or clearing ABS module codes. The dash light would stay on until I drove car down street even a few feet at times and then it would turn off. Seems to require both some steering wheel motion and a bit of rolling distance.

97urS6

Thanks for the detailed response... I went over to the mechanics shop, spoke to the owner. I showed him the VCDS output and he thinks that it might be something that was not reconnected in the ABS system? He is not sure, but is going to have his top tech take a look on Monday.

It appears that the Steering Angle Sensor might be ok.... see VCDS Log output... the top line in the summary below for Module 00. Here is a clip of the important bits from the log file.

Chassis Type: 4E (4E0)
Scan: 01 02 03 05 06 07 08 09 0E 0F 15 16 17 19 25 34 36 37 38 42
46 47 4F 52 53 55 56 61 62 65 67 72 76 77
. . .
00-Steering Angle Sensor -- Status: OK 0000
01-Engine -- Status: Malfunction 0010
02-Auto Trans -- Status: OK 0000
03-ABS Brakes -- Status: Malfunction 0010
. . .
-----------------------------------------------------
Address 01: Engine Labels: None
Part No SW: 4E0 910 560 P HW: 4E0 907 560
Component: 4.2L V8/5V G 0010
Revision: --H01--- Serial number: AUX3Z0E8774746
Coding: 0007773
Shop #: WSC 02313 785 00200
VCID: 2E0604104C16BBF78F5-807A

2 Faults Found:
17981 - Left Engine Mount Solenoid Valve (N144)
P1573 - 004 - Open Circuit
Freeze Frame:
Fault Status: 01100100
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 204669 km
Time Indication: 0

Freeze Frame:
RPM: 133 /min
Load: 72.1 %
Speed: 0.0 km/h
Temperature: 101.0°C
Temperature: 54.0°C
Absolute Pres.: 0.0 mbar
Voltage: 10.795 V

18061 - Please check DTC Memory of ABS Controller
P1653 - 008 - - Intermittent
Freeze Frame:
Fault Status: 00101000
Fault Priority: 0
Fault Frequency: 7
Reset counter: 255
Mileage: 204669 km
Time Indication: 0

Freeze Frame:
RPM: 2179 /min
Load: 53.3 %
Speed: 17.0 km/h
Temperature: 21.0°C
Temperature: 13.0°C
Absolute Pres.: 0.0 mbar
Voltage: 14.097 V

Readiness: 0010 1101
. . .
---------------------------------------------------
Address 03: ABS Brakes Labels: 4E0-910-517.lbl
Part No SW: 4E0 910 517 B HW: 4E0 614 517 N
Component: ESP 5.7 allrad H44 0500
Coding: 0007597
Shop #: WSC 60462 000 00000
VCID: 221EE02008CE0F971BD-8076

1 Fault Found:
00778 - Steering Angle Sensor (G85)
008 - Implausible Signal - Intermittent
. . .
---------------------------------------------------

The symptoms from driving the car this morning are as follows: starts up nicely, no fault lights on the dash, however, when I pull away from a parked position, the ESP indicator light flashes on and off and the ESP system is engaging by applying brakes and removing power from various wheels as if I'm in a corner and sliding... but I am driving straight ahead going very slowly. It will do this for about 100-200 feet then the ESP will fault out (displaying ESP Fault Found on the center display), the ESP warning light will stay on... and the car will drive normally (pretty well the same as last night).

Any thoughts on what this could be?

MP4.2+6.0

Yes, ABS and ESP are of course related since ESP acts on brake side through ABS unit. And they can cross post error codes to the other module like here too. Clear codes in both modules then try again. I have a hunch it is still the overall clock spring unit that has the sensor in it. They need to strip away column trim just behind wheel to get at the connectors if it is only a loose connection like code may suggest. Could be inside unit though too. It logically fits steering work, and if they started moving column shaft a lot or spinning it, it could have screwed up the sensor above. The clock spring units do also fail. Have replaced them on each of my last three Audis over the years, and new S8 has an annoying soft grind to it when first driven and quiet. I can see how if sensor data meantime is junk or coming in spurts why your car would drive weirdly like you are saying--until system gives up, throws the light and then is disengaged.

97urS6

Found some very interesting information this afternoon... I posted up some info on the Ross-Tech website to see if someone there could decipher the VCDS codes and give some tips on additional data that could shed some light on the situation. Someone recommended that I check the Steering Angle Sensor reading, which can be found under Module 03 ABS Brakes, Measuring Blocks, Group 005, box 1.

With the steering wheel straight ahead it should be reading 0.0 degrees. However, mine was reading 360.0 degrees.... sounds like something is connected backwards? Is that even possible? Most connectors can only go in one-way?

Another piece of information is that Group 001 has all four of the Wheel Speed Sensor readings, and they all appear to be working correctly.

It almost sounds like the alignment guys had the steering wheel off and was playing with the wheel angle sensor connector... or possibly the other end of that connector wherever it leads to?

target39

Does the measuring block value of 360° change when the wheel is turned, i.e. turning clockwise increases value and vice versa?

Your mechanics should not have had to play around with the steering wheel unless you had the intermediate shaft replaced as well, so I doubt that's the issue. A four-wheel alignment should only involve adjusting toe in/out via tie rod and control arm adjustment and in severe cases, camber adjustment via the subframe. So no interior/steering wheel work needed.



Try this:
Steering Angle Sensor (G85) Calibration
[Select]
[03 - ABS Brakes]
[Fault Codes - 02]
[Done, Go Back]
Turn steering wheel at least 30 ° left and back straight ahead.
[Meas. Blocks - 08]
Group 005 Field 1 (Steering Angle Sensor -G85-)
Specification: 0.0 °
Tolerance (when straight): ±5.0 °
[Done, Go Back]
[Login - 11]
Or [Coding - 11] if Login is not shown
Enter 40168
[Do It!]
[Basic Settings - 04]
Group 001
[Go!]
[Done, Go Back]
[Fault Codes - 02]
All fault codes should have disappeared.
[Done, Go Back]
[Close Controller, Go Back - 06]

Sometimes a steering angle sensor calibration is necessary when the battery is disconnected and reconnected. Note: you cannot go into the proper basic settings until you have logged in to the module with the code: 40168. You should have the steering wheel completely straight and still when going into basic settings and calibrating it.

Mister Bally

I will guess that the steering wheel was rotated when the rack was removed from the car as part of the process of attaching the steering shaft (two U-Joint shaft) to the replacement rack. A nice PITA to resolve.

MP4.2+6.0

I'll put money on this B-I-N-G-O bet too. Do the math. Pull rack, have to fight with it. Mister Bally and I were both there on our nightmare 5000's 30 years on playing Hell with this. Get it out after barely undoing pressure lines...and steering column connection. Approx zero working room and approx no way to see anything. Most work by feel only, covered with fluid as lines pee on you. Probably spin something a bit along way--many times one way or other maybe. Oops, column turns and doesn't line up quite right when I go to bolt back up. Which way to I go? Left? right? Damn, I don't remember. Flip coin? Correct direction back to 0, wrong direction, oops a...360. Hmmm.

Gotta read through any available posts, check diagnostics, etc., but might turn out that...oh so carefully you need to pull that clock spring unit off column, then rotate the center of it 360/one turn, and put back on. Basically clock spring is either wound a turn tight or a turn loose if I go by the 360 measurement block. But, read manual carefully. I think you can screw it up easily if not pulled off right. And you need to turn it to 0, and not end up at 720 the "wrong" way again. Like why they ship them with a no move (turn) retention pin in the first place. Just like a fire extinguisher and a...grenade.

97urS6

Well, just wanted to report that Mr Target39's recommendation to perform a Steering Angle Sensor alignment seemed to do the trick. As soon as I put the 0.0 degree's entry in Measuring Block 005 (ABS Brakes Module 03)... the codes cleared themselves... and a test drive showed that ESP seems to be working well.

Mister Bally

Thank goodness it can be resolved by reprogramming. Let us know in the event it rears its ugly head again though. Thanks.