abs woes

[Mark Inglis]

Hi all

I am new to this forum so I suppose that warrants a quick introduction, I am a fairly competent mechanicaly minded individual having restored and customised my 1989 mk1 mr2 and also now own a 1999 a4 b5 avant se 1.9tdi afn engine (110bhp) with the 4 speed auto box, i was very much in the dark when i bought this car and have already had to replace a multitude of parts including the auto transmission computer (flooded in the drivers footwell) hydraulic tappets (sounded like a tracter) most of the front control arms, front discs and pads, rear pads (managed to clean up the discs on the lathe) nsr damper, osf spring, osr caliper (some tool had fitted an ns caliper to the os), aux belt tensioner, thermostat, nsr light cluster, nsf indicator, os steering gator, ive also replaced the timing belt, aux belt and air con belt (aircon belt wasn't even fitted)

anyway back to the point in hand, i had noticed that the abs wasnt working even though the abs light was off, having scoured a few forums and youtube someone had mentioned that there garage had "supposidly" repaired there abs by putting a piece of black tape over the bulbs behind the dash, after taking the dash out this was also the case with mine, and after removing the tape and reinstalling the dash I had both an abs and airbag warning light on, the airbag warning light was the usual problem (cable under passenger seat needed wiggling, I will eventually solder the connections to cure) and after plugging in a kkl cable i was able to clear the fault with vcds (shareware version) however the ABS was far more troublesome, it was initially showing an osr abs speed sensor fault (abs open or short to +) (I should add the abs is 8e0614111a) however after replacing the sensor the fault could not be cleared, after some more googling I read that it could be the abs module itself, I managed to get one from the scrappies and after swapping it over it was still showing the same fault, now Im not completely electronically illiterate so I broke out the multi meter and checked, from the multi plug for the abs, all abs sensors are showing a resistance of 1.2kohms (ish) i checked each pin leading to the supposedly faulty sensor and checked it to earth and there was no short to positive, As an experiment i disconnected both rear abs sensors and only the os was showing up as faulty, I assumed again that the abs module was faulty and I ordered a second hand one of ebay, this showed exactly the same error so I returned it, Im now on my fourth module and again showing the same fault, I know for a fact that all the speed sensors are working and this is really driving me up the wall the only thing ive noticed is that with the ignition on and connecting the multiplug to the abs module I can here a few clicks then a slight buzzing then a final click also unplugging the speed sensor from the loom, every sensor is being fed a voltage apart from the osr

any help please

also as I only have a shareware version of vcds I have not been able to adjust the injector timing following the timing belt change, would any kind soul out there be able to help me out setting it properly?

also I'm not sure what to call it but above the stereo where there is a little cubby hole with a little door, now im told that these have a habit of breaking and not staying shut, now last time i was at the scrappies I scavanged a couple and kept them as spares if anyone wants one

regards,
Mark Inglis

[Mark Inglis]

Hi again

a little update, I connected the nsr abs cable to the osr abs sensor to check to see of the sensor was in fact faulty and bringing up measuring block 1 on vcds in abs I am showing a speed reading coming from that sensor when driving so I now know that the sensor is working perfectly as is the inductor ring therefore the fault must be with the cabling from the abs sensor plug to the abs module multi plug or yet again I have another faulty abs module

regards,
Mark Inglis

[Simon.C]

Sounds like you need a fully functioning VCDS lead. I would suggest the following:

Recode the instrument panel so that it ignores any signals from brake pad wear sensors.

Make sure the ABS controller is correct for your car. Does it have ESP? Can you get a part number from the dealer based on your chassis number?

Do your brake lights work? Is the transmission ecu working ok and free from stored faults?

Not sure where the wiring to the rear ABS sensors run, but if you've had a flooded footwell you might find some wiring issues in that area (there's a lot of wiring behind the trim immediately in front of the door aperture, under the glovebox).

[greavsy]

Hi Mark, can i jump in on this. I am having trouble with the Airbag light on my 1999 Avant 1.9tdi. You mention soldering together the wires under the seat. By doing this does the Airbag light still function, ie comes on with the igniton then goes off ? I hear that the new MOT regulations state that all warning lights must function as normal or it will produce an MOT fail. Thanks, Kev.

[Doctle Odd]

Yes the light will still come on and go of during the self test, soldering is just more secure than the plug connection.

Hi Mark, can i jump in on this. I am having trouble with the Airbag light on my 1999 Avant 1.9tdi. You mention soldering together the wires under the seat. By doing this does the Airbag light still function, ie comes on with the igniton then goes off ? I hear that the new MOT regulations state that all warning lights must function as normal or it will produce an MOT fail. Thanks, Kev.

[Doctle Odd]

Best get a full VCDS scan before trying anything else, there's a map on the site of guys that have it so hopefully theres one near you.

[greavsy]

Hi Paul, thanks for your reply, very helpful. I'll get a scan organised. Thanks.

[Mark Inglis]

I'm having a strange problem just now that that vcds cannot connect to the airbag control module, strange as it always did it before, the abs module that was in the car was 8e0614111a and everyone ive tried was the same part no, there are no brake pad wear sensors either (I have replaced all the pads and theres defo none) with vcds connected to the abs control module and the car in motion I get a speed reading from 3 out of 4 speed sensors and if i connect the supposidly faulty right hand speed sensor to the cable for the left hand speed sensor then I get a reading from that as well, I also cut the cables at the abs multiplug leading to the right hand rear speed sesnor and using a multi meter measured the resistance, it was showing 1.2 kohm, the same as the rest so its not open circuit, I also earthed each cable in turn through the multi meter to see if it was shorting to + and there was no voltage so its not short to +, I also connected each cable in turn via the multi meter to + to see if they had earthed somewhere and again no voltage so no short to earth, with the volt meter again with the cables cut I measured the voltage coming from the multi plug (with the ignition on) and there was no voltage (should be a voltage, cant remember what I measured of the left hand one of hand) I did notice that with the multimeter attached to the multiplug and the ignition switched off then switched on that there was a tiny blip of voltage then nothing liek an internal circuit breaker had cut he voltage on the abs module, the last thing i checked was that the multiplug itself didnt have an internal short again by eathing an connecting to positive each cable for the rear right sensor, the thing is the guy that sold me the most recent module was adamant that it was in perfect working order, I know that there are a few cables that run to the dash for diagnostics could a shortto + or - cause the abs module to behave in such a way?

Mark

[Mark Inglis]

holy crap, ive sussed it out, I went back up to the scrappies where I got the abs module and removed the multiplug with some loom and compared the pins to the one on my car and there was a slight difference, for the rear right abs sensor on mine it was pin - space - pin, on the donor car it was pin - pin - space no wonder the rear right sensor wasnt showing up, after connecting vagcom and clearing the codes I now have no abs warning lights and more importantly my abs is fully operational WIN, i now need to sus out why I cant connect to the airbag control module SIGH

Regards,
Mark Inglis

[greavsy]

Hi, i got a diagnostic scan done on Wednesday. The N/S/front Abs sensor is faulty. I'd replaced this about 3 weeks ago with a "Delphi" sensor, has anyone used these parts before ? Are they any good ? The Auto electrician says he will only use genuine Audi parts. The Sensor is £182. 82 from Audi ! He also said the dashboard was corrupted and would need replacing. On a lighter note the airbag fault seem to have cured itself. Can anyone recommend other parts suppliers rather than the main dealer ? Kev.

[Mark Inglis]

hi, get him to check the resistance of the abs sensor using a multi meter before replacing it, should read about 1.2kohm, if its open circuit or zero resistance then its faulty,if the resistance is within spec, then its another problem, if he insists on genuine audi then get one from a scrappies (again check resistance) no more than a tenner

[greavsy]

Hi Mark, i'd already got the car back when i posted so it was to late to get the resistance checked. I've taken the ABS sensor out to have a look at it. It's marked on the end by the Reluctor ring, i'd obviously pushed it down the bore too much when i fitted it. I'm going to run it for a while now i've refitted it and see what happens with warning light. I'll report back to say wether it's made any difference or not.

[Mark Inglis]

remember you will need to clear the fault using a diagnostic tool or vagcom if you have it

[greavsy]

Hi yeah, i know about clearing the codes. Thanks for the reminder tho'. The car's had a decent run today and the ABS light has been on all the time. I've ordered a new Sensor, picking it up tomorrow.

[Mark Inglis]

hopefully it is the sensor and not the module, My first module was defo knackered and it took months to sus out the problem

[greavsy]

Well i fitted the new ABS sensor on Wednesday and so far (touch wood) everything seems fine.

[Mark Inglis]

glad to say that several weeks later and all is still well with the abs, gonna tackle the airbag light now, what's the easiest way to get the seats out?