MK 3 Gti 16v Fault Code - ABS Problem

[dravidham]

Hi,

Firstly happy new year []

Just wondered if I could pick your brains regarding my latest fault.

My car has just had a new clutch fitted and whilst it was in the garage I asked them to check out my ABS wheel sensors as there appeared to be a bit of a problem with them:-
Although the brakes and ABS seem to work very well, basically the ABS warning light comes on as soon as the ignition is turned on and once the car is on the move the warning light never goes out. Shortly after I first bought the car, the warning light would occasionally flash up whilst driving, but over a period of months it has now got to the stage where it just seems to be on all of the time.
When I picked the car up from the garage recently they told me that they hooked it up to their diagnistics and the machine did not pick up any errors on the wheel sensors; however, the machine did throw up a remark 'code 01726 ABS hydralic pump V64 - signal outside tolerance'
The guy in the garage I spoke with informed me that the fault could either be down to a faulty ABS pump or alternatively my ECU(?!!) and he said that it would be trial and error to fix it.
That was not exactly the news I wanted. My MOT is due imminately and I understand that this issue will cause the car to fail the test.
Clearly I want the problem fixed but after shelling out £400 for the clutch, I really dont want to end up having a new ECU AND an ABS pump fitted.
Can any of you tell me your interpretation of fault code 01726 - can the fault be narrowed down to just one component. I am unsure what diagnostics machine was used, but I do know that it wouldn't be the VAG.com one.
Hope to hear from some of you guys.

Thanks,

Dave.

p.s. Great forum by the way - this is my first visit.

[dravidham]

Anyone please?

[adamss24]

The fault code 01276 does relate to a faulty ABS hydraulic pump. Would be a good ideea if you could clean the conectors to (the ABS controler/ECU) maybe will clear the problem. I suggest getting a cheap replacement ABS ECU/controller from a scrapyard and have it codded to your motor-simple to do with a Vag-Com/diagnostic equipment. If the probblem its still there, then i will look into replacing the ABS pump as i dont think its serviceable. Also pay attention to the front wheel Abs sensors as if one faulty it may make the pump look faulty. Clean the rings and the sensors from grime/rust and check for chuffed wires and plug the sensors all the way in their sockets/holes. Please note that when there is a fault with the ABS unit, the ABS features will be DISABLED and your car will behave like one with no ABS brakes so drive carefully please !

[jp_paul]

ABS faults can be caused by cruded wheel speed sensor rotors which are attached to the end of the driveshaft as stated above, or faulty sensors. Another simple thing to do is check the resistance of the sensors. If they are not almost identical and around 1000-1300 ohms, then one is faulty. You can also check that an AC voltage of >65mV is induced with a rotating wheel. No or low voltage means duff sensor. Check this carefully before replacing the ABS pump or ECU as pumps aint cheap and ECUs very rarely go faulty.

Hope that helps.

Jp

[dravidham]

Thanks for the replies guys. I've been unable to make any further progress with finding the fault as my starter motor solenoid has now also decided to give up the ghost.

Now I can't even start the car

I'll keep you posted.

[jp_paul]

Try a big hammer on the offending solenoid whilst engaging it. Sometimes they can stick and a tap is enough to free them off. You never know, you might have some joy!

Jp

[Trev95]

Hi Another new member here. Wish I had picked up on this site before. Could have saved myself pounds and alot of time.

Following on from Dave's ABS problem, I have a similar problem with my Audi A2 1.4. Sometimes when I switch on the engine the ABS warning light and the Traction control/electronic stability program (ASR/ESP) warning light stay on, other times it is OK. At moment they seem to stay on pretty well everytime. I took it to my garage last September, not an Audi dealership, but usually pretty good and after much scratching of heads they replaced the diagonal acceleration sensor. For a while about 3 weeks all seem to be well but then the problem started up again. Initially fairly intermittently but as I say much more frequently now. My garage asked me to keep a note of how often this happened and drop it back but before I do, it is useful I think to get this forums help.Particularly as the garage have struggled to find the answer and clearly have not to date.

Kind regards and thanks for any help

Trev

[dravidham]

Try a big hammer on the offending solenoid whilst engaging it. Sometimes they can stick and a tap is enough to free them off. You never know, you might have some joy!

Jp

Thanks for the reply and tip. I'll be totally honest with you - I tried the hammer treatment first (out of anger at the time ).

I'm gonna order a new unit tomorrow and then once I have fitted it (assuming it solves the problem) I will then need to get back to the original problem I had of looking in to the ABS fault. MOT runs out on 14/01/07 so not much time now before I will not only mechanicly but also legally off the road .

I've loved this car for the last 11 months of ownership but after dropping a clutch 3 weeks ago and then getting the latest 2 problems literally straight afterwards, quite frankly I now hate the thing in a big way now.

Kind of guess my forthcoming weekend will be busy getting covered on oil :-)

I'll keep you guys posted on the progress.

Cheers,

Dave.

[RJS_90q]

On my 90 quattro I have experienced ABS light problems previously after the car was in the garage for some MOT work on the front suspension. They were not able to fix the ABS issue (they had caused) easily hence I ended up working on it myself. The car is too old to have any codes (analogue system). I ended up setting up the wheel sensors gap using an oscilloscope to check the output level and matched all four wheels to each other. No problems since

On the Audi 90 there is a special plastic moulding fitted to the wheel sensor to help set up the gap.

Probably worth asking the garage to check the wheel sensor setting gap as it is quite a sensitive setting,

Hope that this helps,

Regards,
Bob

[VR5_Lee]

I have the same problem on my 1.6 Mk3 Golf,

Replaced all sensors (cost a fortune),
Cleaned sensors area myself (garage must have not considered it necessary),
Re-set sensor positions...
None of this worked - still scratching my head over the problem 18 Months on - But...

To get through the MOT's I just pop out the plastic dash trim and unplug the bulb. Eh Presto! Pass everytime.
I plug back in after test to make sure I don't forget.

Hope I got to you in time,
Lee

PS - What I thought was a solenoid problem on same car (turn key - click, click, click, click, nothing) turned out to be knackered battery - no previous warning so thought it was starter motor - £90 later and it turned out to be the battery - see'f you can borrow a mates to jump off to try it.