ABS Problems Assistance Please

Hi,

I have an 1.4tdi jan 2002 and am experiencing abs problems.

I have read all related posts and am now at a loss as to what is going on.

i think i have the mk60 abs pump fitted to my car

This all started about two weeks ago.
all three lights sound and 3 beeps shortly after moving off. (two orange lights and red flashing warning triangle in display(non dis))
at first it did it just once about two months ago, in the last two weeks it went off on the motorway one day and has persisted ever since.

i have vag-com and in abs shows the fault "right front sensor intermitent electrical fault", as i had a wheel bearin gdone on this wheel last feb i checked this first.

last saturday i removed and cleaned sensor, checked cabling reset ecu.
this worked for 1 day until going to work on the monday and it going off on the motorway again.

thinking it may be the sensor i bought a replacement sensor.

this saturday i removed the old one and replaced, i also considered an intermitent fault in the wiring from the top of the strut to the connector, no fault found (also +12v when ignition on), measuring blocks on abs controler show brake pedal working.

so sunday 8 miles traveled (some over a very bumpy country track) no lights or annoying beeps, i have noticed however when parking up at a slow speed i notice sometimes and only sometimes the abs on the front right (the one which the ecu throws up a fault for) chatters slightly for less than a second, this has only happened since the fault started a couple of weeks ago.

this morning i set off for work , as it was icy i tested the abs which chattered as usual and stopped the car (5mph) and also traction was showing when wheels spin ans usual but within 1 mile the lights return and three beeps, so i am back to square one!!

i considered the brake switch (this was replaced in april 2010) but this shows as working in measuring blocks for engine and abs controllers

i also considered the abs pump but as tested this morning seems to be working ok until the lights come on and the ecu shuts down the system.

i am now thinking abs ecu as it is in the engine bay and subject to cold/wet conditions, maybe its a short in the main connector??
tonight i am going to try to remove main ecu abs connector and spray contact cleaner, is there any way to expose the abs ciurcuit board without removing the abs uinit so i can inspect for water ingress and spray contact cleaner???

any ideas welcome as its driving me mad!!!

is there any other locations to check for water ingress which could be causing an intermitent fault in the abs circuit?? or has anyone else had exactly the same problem and diagnosed it without paying the stealership!!

i have access to a replacement abs pump and ecu as a last resort (from scrapped vehicle) but would rather not do this if it can be helped.

thanks in advance

Simon

I'd suspect your sensor or bearing to be honest - if you've had a new bearing fitted, unless it was an OE one and it was fitted correctly (and by this, I mean it has been pulled in to the correct depth), then you're likely to have problems with the sender ring giving a proper signal (the sender ring is incorporated into the bearing).

Don't do anything to the ABS controller - it's a pricey bit of kit at around £1400, so just a visual inspection and possibly some switch cleaner in the multi-plug and that's it.

Cheers,

Mike

abs

Mike,

Thanks for the reply,

Dont know if you remember but i had the head gasket problem on buying my a2 earlier in the year, the bearing was changed at the same time on that side, if it was the ring though wouldnt i have seen problems earlier,(bearing replaced feb and first abs fault shown in september x1 then nothing until about two weeks ago) i have replaced the sensor this saturday and this has made no difference.

would it be worth checking the tightness of the large hub nut?? as the garage that did the bearing i lost trust with as they failed to diagnose the head gasket and it ended up going to another garage and if so do you know what size socket it is?

is there a way to look at the ring remove it from the hub to inspect or is it a garage job?, i did peer through the abs sensor hole with a torch but could not see anything.

any other ideas welcome.

i do have access to a scrap vehicle and abs pump ecu unit which i am confident i could pick up for a nominal amount.

Simon

abs

Today it has been a bit better however turning hard left say at a roundabout tends to set the lights flashing and the dreaded three beeps could it be the hub moving under hard turns left?

I had similar occurances to yours a while back. Started off with intermittent orange warnings then a few reds here and there and then the LHS ABS started kicking in around all right hand corners etc.

All resolved now.

I cant tell you what it was as did a variety of bits:

Cleaned out the bearing ring and all sensors.
Checked calibration of YAW / lateral acceleration sensor
Basic setting / bleed of hydraulic pump.
Full brake system bleed
Replaced brake pad wear connector
Changed to bilstein B8 shocks / FK springs

After the above I had no more problems.

John

Hi Simon
Unlike many cars, the large hub nut only locks the driveshaft in position. Be aware the nut has integral locking tabs which are damaged when the nut is loosened.
The hub bearing assy is an interference fit in the housing but the assy can move - more info here - http://www.a2oc.net/forum/showpost.php?p=48977&postcount=1
I understand the ABS pulse ring is built into the oil seal or bearing so there is nothing that can be done with the ring other than replace the complete hub and bearing assy.
Sorry I can't offer anything more constructive advice

Cheers Spike

Abs

Thanks for the pointers

i am getting no tapping or noise from the bearing.

removed the abs large connector from the abs pump unit ecu and gave it a spray with contact cleaner, this has made no difference.

the lights come on now about 1-6 miles from home and after a stop key out and engine restart i get a further 6 miles or so before the lights come on.

whatever it is is intermitent, it can come on going in a straight line, turning left or at any point brake pedal pressed or not pressed???

i have ruled out the abs sensor connecting wire as even over a very bumpy country track it did not set the lights off and i get a good 12v supply to the connector with the ignition on.

regarding the above post can anyone explain how to do the following

Clean out the bearing ring and all sensors (in particular the front right).
Check calibration of YAW / lateral acceleration sensor
Basic setting / bleed of hydraulic pump.

I have registred vag-com and am able to get to the basic settings/logon /measuring blocks.

dont like to be beaten by a car!!!! but its getting rather annoying now!!

Simon

Abs

Well i popped into my local vag specialists (not stealers) and explained the issues i was having.

They always seem to be helpfull and i have had parts from them at the same price as the dealership too (i have no association with them) just praising good service.

Walkden VW Centre
54/56 Manchester Rd West, Little Hulton, Manchester
0161-790-5483

The head mechanic advised me to check that the new abs sensor i have fitted is seated correctly as now i am getting longer between abs lights showing since changing it, i do remember i could not get it fully flat when refitting the new one, i am talking max 1mm at the most?

The mechanic said he normaly hones out the hole with sandpaper or similar where the abs sensor goes in as the hole commonly rusts making reseating a problem, this in turn makes the sensor not fit correctly by only a small amount but this can cause intermitent abs problems, i am also going to take the advice of a prev poster and spray some wd 40 through the hole as well to hopefully dislodge any c**p from the sensor ring inside the hub.

The lights now only seem to be coming on above 50mph since changing the abs sensor.

I will report back if this works.

Simon

As your mechanic advised its critical the ABS sensor is fully seated. These magnetic pick-ups normally operate with an air gap of 1mm or less so an additional mm would double the air gap and make the signal from the sensor extremely weak. Clean out the hole as suggested and scrape any rust off the flange mounting surface to ensure the sensor is correctly seated

Cheers Spike

I had the exact same problem on the front right with the same symptoms. Drove me nuts for ages on a 51 plate tdi. After suspecting a corrupt feed from the pick up ring within the hub assembly I changed the full hub at the local VW specialist and this cured the problem. Garage advised that the full hub be changed as this rules out any issues with bearings/sensors not being seated properly. Garage wouldnt even consider bearing change or any other supplier other than VW/Audi for the hub .Hope this helps. Cheers Davy

Well i have removed the sensor like my local vag specialist advised, cleaned out the hole and mating surface with a dremel and sanding stone back to bare metal , cleaned all the dust away (only took a few seconds) before squirting wd 40 through the hole as suggested on prev post.

On clearing the fault code it is now back to the 3 beeps and lights going off within a few yards of setting off so it is now worse!!!!

Getting rather fed up now, i am going to change the connecting abs cable tomorrow and then give up on it if that dosn't work!!

Simon

..........or get the hub looked at, in case it has shifted or the signal ring is b****red

John

also, prior to these events happening did you do anything in the control module???

As i know for a fact that there is an abs test sequence you can get the car to run which puts abs into a different mode.

I did this by mistake and until I cleared it the car gave a red error, the 2 abs lights came on and the beeps.

As soon as I looked up how to complete this test sequence and did it, the abs reset and everything went away.

Again this will be in the elsawin under brake section and VAG self diagnosis

John

i cant find this test sequence in elsawin can you give me a pointer.

do you mean test sequence on the abs controler via vag-com?

bobsimes said:

i cant find this test sequence in elsawin can you give me a pointer.

do you mean test sequence on the abs controler via vag-com?

Click to expand...

Go into elsawin

Then go to running gear

Then running gear self diagnosis for ~ESP

Then Self Diagnosis VAG inspection service

Then Self diagnosis

The select Safety precautions and general notes on fault finding.

Read through that page.

John

Also under self diagnosis it has a section called performing self diagnosis.

You could go through all those tests / settings and see if they alleviate the problem

John

Its the pick up ring within the hub its starting to break up causing eronious and corrupt info to be transferred to the abs sensor.I changed the wiring also prior to changin the hub and it did nothing.

Thanks Davidmac

I cant afford it before Christmas but will book it in at my local vw/audi specialist for a new bearing however it was only changed in march this year and suspect the garage (wouldnt go there again after seeing how they went about taking the old bearing out, mis diagnosed a head gasket failure as a water pump and tried to rip me off for labour) may have not installed the bearing correctly and damaged the abs ring??

There is an ABS cu and pump at my local breakers (£25)
as an insurance policy in case the ecu/pump is at fault do you think it is worth me buying it and keeping it until i get the bearing changed??

Simon

bobsimes said:

Thanks Davidmac

I cant afford it before Christmas but will book it in at my local vw/audi specialist for a new bearing however it was only changed in march this year and suspect the garage (wouldnt go there again after seeing how they went about taking the old bearing out, mis diagnosed a head gasket failure as a water pump and tried to rip me off for labour) may have not installed the bearing correctly and damaged the abs ring??

There is an ABS cu and pump at my local breakers (£25)
as an insurance policy in case the ecu/pump is at fault do you think it is worth me buying it and keeping it until i get the bearing changed??

Simon

Click to expand...

You'll need to make sure its the same as your one, but if you have run through everything else then its prob the signal ring and that garage messed it up

John

This is a very interesting, but annoying thread.

I have exactly the same symptoms with my new A2. The problem started on Saturday morning and as yet I’ve not done anything except scanned & cleared the fault codes.

I’m getting 15 to 20 mins driving before 3 beeps and warning symbols re-appear.

Address 03: ABS Brakes Labels: Redir Fail!
Control Module Part Number: 8Z0 907 379 C
Component and/or Version: ESP FRONT MK60 0101
Software Coding: 0019591
Work Shop Code: WSC 00000 785 00200
VCID: 48948EDD42CF
2 Faults Found:

00285 - ABS Wheel Speed Sensor; Front Right (G45)
008 - Implausible Signal - Intermittent
00285 - ABS Wheel Speed Sensor; Front Right (G45)
012 - Electrical Fault in Circuit - Intermittent

Simon,

bobsimes said:

There is an ABS cu and pump at my local breakers (£25)
as an insurance policy in case the ecu/pump is at fault do you think it is worth me buying it and keeping it until i get the bearing changed??

Click to expand...

If you buy the ecu & pump, and they are for MK60, if you don’t use them I’ll buy them off you.

Cheers

Jeff