Electrical gremlins - help needed!

[DJSF1966]

A week ago the ABS & ESP warning lights came on. At the same time the Rear Parking Sensors, Folding Mirrors, Speed-sensitive Steering and "one touch" control for the Sunroof all stopped functioning (the sunroof would still work if you "pressed & held"). Everything had been working perfectly prior to this.

Later in the day the ABS/ESP lights went out again, and everything else started to work again. And finally that day, the ABS/ESP lights came on again, all the other things stopped working, and the Engine Management Light came on as well (just for good measure!).

The local Audi Main Dealer has now had the car for 3 days. The initial fault reported was a faulty ABS sensor (front, near side - which is apparently coincidently the area of the venicle where the electrical control units are located for all the other equipment that stopped!). The ABS sensor was replaced, and initially showed the fault as being cleared (dash lights out). However, during the test drive the lights came on again The fault is still showing as the sensor that has been replaced (it has been checked and is functioning correctly).

The Dealer is now going through an "elimination" exercise, and the problem seems to be stumping even a "Master Tech". In addition, the diagnostic bill is rising (although in fairness with cost-splitting by the Dealership).

Has anyone experienced anything similar? And if so, how was it resolved? Personally I'm struggling to make the connection between the ABS fault and the temporary failure of all the other components - even though as soon as the warning lights go out, everything else immediately starts to work...

All suggestions welcome!!

[nihc]

Hi,

Have you done a Vagcom ( VCDS) scan of the car for faults? What errors were found? Can you post the dealers scan here?
I think the ABS sensor fault will just be a symptom of something else that's bringing everything else down.

My wife had a similar problem with her TT. The whole car would go mental with every fault under the sun - most of the time it would be fine.

I traced it to a third-party relay case shorting to the car's metal frame.

I would start by taking the fuse box out and checking all of the fuse connections - you could check if all of those contyrol units are on a common fuse by pulling them in turn.
It must be some sort of power supply problem. The Vagcom scan may give clues.

I don't think the control units are anywhere near the ABD wheel sensor. Easily looked up on Erwin, though.


Regards, Chris.

[BlingBling]

Sounds obvious but have they checked the fuses? I recently had all kinds of lights showing up on the dashboard with accompanying codes, 17 in total. Turns out one of the ECU fuses, there are 3 in total, had blown. IIRC it was fuse no32. Virtually all of the 17 codes were short to ground related codes. Some purely because of the wiring i.e. faulty 02 sensors, faulty MAF sensor. Your problem could just be the same. As above get a list of the codes and ask if they checked the fuses just to make sure the dealer is not trying to pull your pants down.

[DJSF1966]

Well, the results are in. . . After a week of diagonstics, I was told tonight that they believe the fault is in the ABS Control Unit. Cost of part £1600 (inc VAT), so total bill will be a little over £2200.

?<#%^^|¥¥$[{{#%@?!/(). !!!!!

Needless to say I'm not a happy camper. . . but there seems to be little option but to proceed. On the plus side, in addition to the diagnostic cost to me, they have racked up a further £850 spend which I'm not being charged for (otherwise bill would be £3000+!! Should I be gratefull for (small) mercies?

I had been comtemplating an S8 which had recently become available over here, but that looks financially scuppered now.

The joys of S-car ownership?!?!

[BlingBling]

Well, the results are in. . . After a week of diagonstics, I was told tonight that they believe the fault is in the ABS Control Unit. Cost of part £1600 (inc VAT), so total bill will be a little over £2200.

?<#%^^|¥¥$[{{#%@?!/(). !!!!!

Needless to say I'm not a happy camper. . . but there seems to be little option but to proceed. On the plus side, in addition to the diagnostic cost to me, they have racked up a further £850 spend which I'm not being charged for (otherwise bill would be £3000+!! Should I be gratefull for (small) mercies?

I had been comtemplating an S8 which had recently become available over here, but that looks financially scuppered now.

The joys of S-car ownership?!?!

What do they mean "believe"? I'm sorry but I would like more confirmation of the exact fault if the end bill is north of £2000. What codes did they pull? did they check the fuses? Did they check the MAF? Have they checked the earths? The MAF ABS and ECU are all on the same circuit so a fault one more of the aforementioned could raise a code even if the item itself is not faulty.

Here is the list of codes that were logged when the ABS, EPC, CEL all came on:

17980 - Left Engine Mount Solenoid Valve (N144): Short to Ground P1572 - 002 - Lower Limit Exceeded
17833 - Tank Vent.Valve Short to Ground P1425 - 002
17984 - Right Eng. Mount Solenoid Valve Short to ground P1576 - 002
17843 - Secondary Air Pump Relay (J299): Short to Ground P1435 - 002 - Lower Limit Exceeded
17829 - Secondary Air Injection Solenoid Valve (N112): Short to Ground P1421 - 002 - Lower Limit Exceeded
16440 - Oxygen (Lambda) Sensor B2 S2: Heating Circuit: Malfunction / Open Circuit P0056 - 004 - No Signal/Communication
16421 - Oxygen (Lambda) Sensor B1 S2: Heating Circuit: Short to Ground P0037 - 002 - Lower Limit Exceeded
19474 - Valve for Exhaust Flap 1 (N321): Short to Ground P3018 - 002 - Lower Limit Exceeded - Intermittent Signal too Low
16486 - Mass Air Flow Sensor (MAF/G70): Signal too Low P0102 - 002
16415 - Oxygen (Lambda) Sensor B1 S1: Heating Circuit: Short to Ground P0031 - 002 - Lower Limit Exceeded
16435 - Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 2 Sensor 1) P0051 – 002
17522 - Oxygen (Lambda) Sensor; B1 S2: Internal Resistance too High P1114 - 002
17548 - Oxygen (Lambda) Sensor; B2 S2: Internal Resistance too High P1140 - 004 - No Signal/Communication
18265 - Load Signal: Error Message from ECU (ABS module)
P1857 - 35-00 - -

All the above was down to a blown fuse. If you have the time try and get an independent to have a look.

Good luck

[DJSF1966]

Hi BlingBling,

Regrettably I'm not aware of any independant Audi specialists in NI, and the level of diagnostics involved is not within the capability of the guy who does my routine servicing (he doesn't have Vagcom).

I'm going in to see the Dealer at lunchtime today to discuss. Let battle commence...

Many thanks for the info above.

[Jez141]

Only just seen this but i had similar thing to this and it was a bad cell in the battery as you went to start the power drop caused many systems to reset as if battery had been disconnected. abs esp etc. and after driving a short while the sensors reset as usual also the one touch windows needed resetting.I just replaced the battery and cleaned the terminals too just to make sure dont know if this will help? Jez

[DJSF1966]

To all that replied and offered assistance, please accept my thanks & appreciation.

The source of the problem was finally traced to the ABS Control Unit after the Dealer worked the car for over a week, and had great chunks of it taken apart (as I saw on several visits to the Workshop) . I had a very detailed discussion with the Master Technician and agreed to go with the repair (no real option!).

ABS Part cost £1600, Labour £1500, so total £3100..... Audi UK & Dealer contribution £850 each, so final cost to me £1400. Given that the car is almost 8 years old, and is serviced by an independant, I'm both surprised and grateful for the £1700 contribution.

I will also say that the Service Manager provided excellent customer service. So other than a (not as big as it might have been) hole in my wallet, it's been an acceptable experience (which could not be said of similar occasions in the past).

The car's now been back on the road for 10 days and all seems to be fine - PHEW!!

[BlingBling]

Did they give a reason as to why the module failed?