ABS warning light, ABS pump internal wiring

[StormyTommy 0]

Have been getting ABS warning light coming on intermittently on my 95 VR6.

At first it only came on very occasionally and cleared on ignition off/on, but gradually has become more frequent till at times it came on 10 minutes into most journeys and wouldn't always clear immediatly. It seems to be temperature dependent, i.e. comes on if car very cold or hot, but there seems to be a 'Goldilocks' temperature in the middle where it doesnt come on! MOT is due soon so need to get it sorted.

 

Have done a lot of searching on the forum and some checks from what I've read on here.

VAGcom on the ABS module shows a 00276 - ABS Outlet Valve: Left Rear (N136) Fault. I have occasional speed sensor fault codes but 99% of the time it's just 00276.

Removed ABS ECU and no signs of any corrosion or water damage.

Unplugged connector to ABS pump & cleaned pins/connector. Fault went away for a few days, but did return.

Measured resistance across pins at ABS ECU back towards pump, Outlet valve Rear Left = 8.6 ohms, other outlet valves = 3.3 ohms (specification of 3-5 ohms). Resistance of wire from ECU to pump connector was ok.

 

I suspect that the Teves 4/EDS ABS pump has the common problem of cracks in internal flexable copper ribbon cable from its external connector to valve block. This would explain why it's temperature dependant and perhaps movement of the connector while cleaning it cleared fault for a while. I plan on either replacing unit with a secondhand one or trying to repair existing one.

 

Questions:

1. Will ABS pump from any other cars (eg VR6 Golf) work ok in place of the Corrado part?

2. Removal/fitting of ABS pump; has anyone got a list of steps (or link to a relevent forum posting) on replacing the pump, eg. what parts do you need to remove to get access, how do you take off the 2 inlet/outlet pipes at the top left and how is the pump itself held on? I have read its important to depressure the system before removing lines and that bleeding after replacement can be a problem - any other gotcha's?

3. I'm considering removing pump and trying to repair the internal connector - anyone got any advice on this repair?

[muppetlab 0]

Hi there let me know if you get this sorted. mine has a similar problem in that the abs only works when car has been sitting in traffic for like over 30mins and is way hot i mean 100+ then it all works perfectly until it cools down and then the little red light peeks out and no abs. I am pretty sure this is not a sensor as why would the engine bay temps make a difference? I am thinking maybe the pump needs bleeding somehow and that the heat is expanding any air and either moving it or making enough pressure to make it okay?? just guessing. :) jez

[MikeVR6 0]

Mine has the same thing going on. So please let us know how you get it fixed. I've already tried a new ECU and ABS Pump unit :(

Mechanics bills are mounting up.

[vw corrado storm king 0]

MY ONE NEEDED A NEW ABS PUMP THERE WAS SOME CRAP STICK IN THE VALVES INSIDE THE PUMP

 

DO HAVE SOME PAPER WORK WITH SOME DIAG CHECKS YOU CAN DO BUT SOUNDS LIKE IT IS THE PUMP

 

IF I REMEMBER WILL POST THEM ON HERE TONIGHT

[MikeVR6 0]

Ok haks look forward to reading those.

[muppetlab 0]

oh dear not what i wanted to hear... wish you had said it was just a sender or a fuse much less expensive.

[MikeVR6 0]

There's a shop on E-Bay selling reconditioned units for £70 - £100.

http://tinyurl.com/yb6gw4k

 

But the mechanic already tried a "known good" pump and it did squat :(

[muppetlab 0]

Thanks, i bought a 2nd hand pump and ecu a while ago when i first had the problem but was kinda praying that it would just be a sensor. Doh. guess i will have to bite the bullet and swap the pump.

[MikeVR6 0]

muppetlab I don't know if you've done this already. But before swapping anything get the car plugged into a diagnostic computer and read/clear any faults from the ABS ECU. Someone with VAGCOM can do this or your local VW Stealer. My problem is the ABS ECU does not communicate at all with VAG Diagnostics. Hopefully yours will just be a wheel sensor. They're only £20 or so each and 10 minutes to replace.

[muppetlab 0]

Yep was going to vag com it after i check the rear sensors. Have replaced one front one having worked out it was shatfed. Problem is mine is intermitant and it seems to work perfectly occasionally and then play up. Was planning to whip i round for the mot when the dreaded light is not on. although failing that i think there might be a piece of wire finding itself from the abs light to the oil pressure sender switch :wink:

[muppetlab 0]

Found o/s rear sensor fubar so fingers crossed its that or i will be chucking my toys out of the pram. Beginning to lose heart after wheel bearings, track rods, thermostat, front abs sensor and now radiator leaking and cooling fans packed up, all in less than a month. I know it will be okay once she's good and running fine again but sometimes it just gets a bit much and i start coveting a nice newer reliable hatch but they are all so damn faceless and boring. Oh and they lose twice what i pay to keep the C on the road in depreciation a year. Just need to get on top of the servicing as i am sure my ole gal has been neglected badly despite all the shiny bits.

[StormyTommy 0]

Took Corrado for MOT, The ABS check light stayed off during the test BUT it failed mot on corroded rear brake pipe and bulging front brake pipe :censored: ...

I plan on getting garage to replace brake pipes, but am thinking I should try doing repair of pump beforehand as garage is going to have to bleed brakes afterwards and light may come on for the retest.

Not sure if its clear from post above but the testing I did pointed to a specific problem with the ABS pump assembly in that I'm getting a high resistance reading for one of the valves. This matched the error code Vagcom is showing.

 

Looks like the coolent expansion tank has be moved out of the way to give some room.

Has anyone got a list of steps (or link to a relevent forum posting) on replacing the pump, especially how do you take off the 2 inlet/outlet pipes at the top left of the pump?

[StormyTommy 0]

Got a quote for ABS pump swap out from a garage, approx £160 all in, with me repairing pump or supplying a secondhand one.

Mechanic said the 2 pipes into the top left of the pump just pull out, which supprised me as I thought the pressure would force them off?

[muppetlab 0]

Got a quote for ABS pump swap out from a garage, approx £160 all in, with me repairing pump or supplying a secondhand one.

Mechanic said the 2 pipes into the top left of the pump just pull out, which supprised me as I thought the pressure would force them off?

I think if you follow the two (push in) pipes they just go to the reservoir so are not under pressure anyway, I might be wrong though.

[StormyTommy 0]

Car passed MOT after brake pipes replaced :clap: , ABS light is very rarely coming on so I'll wait till warmer weather before trying to get the pump out and repaired/replaced.

 

muppetlab : agree with mikevr, its worth getting car Vagcom reading done.

In my case it pointed to a specific valve and when I measured from the ECU back to the pump on that valve it was sometimes out of spec.

If you have'nt swapped ECU, and want to try that, it's a really easy one to do.

Here is the procedure I used to remove ECU and fault find towards pump.

 

Remove connector to ABS ECU. Located along side of passenger footwell, behind plastic panel in front of door hinges - 2 screws behind plastic caps and 1 plastic screw in footwell. Remove/loosen nuts to release ECU module then lever up crome handle to unplug connector.

Can now measure from the connector back to the Teves mark IV ABS pump, checking the resistance of the solinoids in the pump, this is one of the checks the ECU carries out to on the pump to make sure all the valves will work if needed. If any are outside of range it disables the pump, raises the ABS warning light and a Vagcom error code.

 

Outlet valves should be 3 - 5 ohms, Inlet valves 6-8 ohms.

Connector layout: 55 pins in 3 rows, 1st row (longest) 1-19, middle 20-37, 3rd 38-55. wire loom joins from the 1/20/38 end.

These are: pins to measure across, wire colour, solinoid being measured, values I got.

 

33-36, W, Outlet valve Rear Left = 8.6 ohms (outside of range which matches Vagcom error I get of "00276 - ABS Outlet Valve: Left Rear (N136)"

33-2, BK-BL, Outlet valve Front Left = 3.3 ohms

33-21,G, Outlet valve Front Right = 3.3 ohms

33-20, BL, Inlet valve Front Left = 6.7 ohms

33-38, GY-R, Inlet valve Front Right = 6.7 ohms

33-54, GY, Inlet valve Rear Left = 6.6 ohms

 

Measured from pin 33 R-Y, could also use pin 3 R/Bk

 

To check the resistance of the wire to the pump I measured from pin 36 on ECU connector to connector on pump (white wire) middle left of plug and got 0.1 ohms.

Conclusion: internal pump wiring or solinoid is faulty to outlet valve rear left. Only other diag step would have been to measure resistance on the pins of the pump connector itself in the engine bay. Pin for White wire (far Left) to pin for Red/White for Outlet valve Rear Left . However, its difficult to get a meter probe onto those pins, need to make up 2 small connectors to slide onto pins.

 

Hope the above can be of help to someone.

[muppetlab 0]

Thanks for the info, hopefully might have sorted mine, have traced faulty rear sensor and plugged new one in and light went off. Yet to see if it stays off once fitted properly and rolling. Fingers crossed as Mot next week. On the plus side i am fitting the mk4 calipers and new pads and discs to the back whilst i am there so hopefully nice new rear brakes. Cheers

[huggy 0]

I have a problem with my abs 2 will have to get it up and have a good look at sensors hopefuly someting wron there, turns out the abs light was unpluged :censored: ,

This thread however looks like it should help me solve the problem!, bloody abs who needs it any way my old polo, golf, escort never had it and when the wheels locked up i just took foot off and on brake pedal tap dancing foot lol HUFFFF LOL :nuts: dont think it should be an mot faliure just a recomendation maybe fail if not repaird at next mot

[muppetlab 0]

I have a problem with my abs 2 will have to get it up and have a good look at sensors hopefuly someting wron there, turns out the abs light was unpluged :censored: ,

This thread however looks like it should help me solve the problem!, bloody abs who needs it any way my old polo, golf, escort never had it and when the wheels locked up i just took foot off and on brake pedal tap dancing foot lol HUFFFF LOL :nuts: dont think it should be an mot faliure just a recomendation maybe fail if not repaird at next mot

If the mot man knows his stuff its a fail i am afraid. Light should be on and then light must go out when started etc. Some turn a blind eye if the lights disconnected depends how friendly you and the mot man are :wink:

[muppetlab 0]

Right, well i spent best part of two days stripping the rear brakes and replaced faulty sensor. Fitted MK4 calipers, new pads, bearings, discs the lot. Bled all 4 corners, master cylinder and abs pump. My pedal is now rubbish, spongy as hell but can get the backs to lock up. Initially the abs light went off but when i got annoyed and did an emergency stop the abs kicked in then the bloody light came back on :censored:

Restarting the car the light has gone off, is this normal?? Would air in the pump cause a fault to light the dash abs light? Are Mk4 calipers bigger pistons because i just dont see why the pedal is so crap. It was hard as rock before i changed the calipers. Wish i had not bothered now. Really pissed off with the car as i am shattered from working on it outside in the cold and snow only to find its worse than when i started. Almost had enough and would get rid of the damn thing if it had not cost me so much that i will never get back if i sell it whole. Dont want to break it but thats what i am thinking now/ :mad2:

Any help someone please??? Just tell me the pads need to bed in and the brakes will be spot on and i can sleep happy. Tell me i need a new M/C or that my abs pump is buggered and there will be one more corrado in pieces before long. Typically the mot is next week and its my daily drive. If i have to get in the works van because it cant pass then i dont think i will have the motivation to sort it. Gutted as i really liked driving it and it was a teenage dream of mine to own one. Everyone told me VR's were money pits but i think i must have been deaf as it seems they were right. :pale:

[casual 0]

Previously i have stripped mine down and replaced the filters etc, you would be shocked how much **** is in there. mine worked perfectly after that. cant remember the code it was throwing up tho.

i remember my stomach turning the first time that light came on :gag: :lol:

[huggy 0]

hey m8ý bare wirh it im sure youl have it fixed soon, gota take the rough withe the smooth as they say.

[muppetlab 0]

I will stick with it. Did 200 miles in it today and the abs light comes on intermitently now so i reckon its a cheap sensor thats at fault. Buy cheap buy twice as they say. The brakes are okay apart from pulling to one side at the rear :roll:

They actually work quite well and stopping is good its just the pedal travels a lot more than it used to, and i am not sure if thats the mk4 calipers or if i have still got air somewhere in the lines. Will try and bled the :censored: again tomorrow. Going to try and get a copy of vag com for my laptop so i can plug in and see whats what. Buggered if i am paying Vw dealer to do that!! Have thought long and hard and i either sell it as is very cheap, break it or keep it. Selling it cheap is not an option as i have uprated suspension, big brakes and it has good spec leather etc so i want to keep it. One option might be to strip the interior and sell bits and just keep it as a track car but would rather use it every day. Might just bite the bullet and put it into the garage and get them to sort it. I know i would miss it if it was gone so it will stay in one form or other, just need a years mot ticket on it.

[StormyTommy 0]

Hang in there, hopefully its just a bit of air in lines that will come out with a second bleeding - esp. now that its been driven for a while. Vagcom should give you clear pointer to whats putting on ABS light.

Brave doing a big job like mk4 brake upgrade in this weather, I'm trying to put maintenance off till its warmer, but had to crawl under her this morning to temporally reattach heat shield to exhaust - now I've got to get it welded.

MOT time is always stressful - hope you get a pass, real shame for another one to get broken up!

[muppetlab 0]

Have bleed the m/c again and the pump and the pedal feels a bit better, but can feel the back brakes pulling the car to one side under braking so hopefully its air in one side and not a problem with the calipers :shock:

Figured the faulty sensor out, just got to cross fingers now as just remembered it had been decatted when i bought it, doh!!

Doubt i will break it as i would rather keep it as a track car, than destroy it as its not that bad. I am sure everyone has spells when nothing seems to go right with their car, but when its all working its great. Just got to refind the love and a years Mot and it will be happy days. I have thought about getting something else, but to be honest i have had loads of cars in my past from mk1 golfs and land rovers to lotus and porsche and none did everything i needed. The corrado is as close as i have got to car perfection, its got good looks, nice turn of speed, bit different from the crowd and it makes me smile (sometimes)

[huggy 0]

Ive just finished sorting out my raddo one abs senor replaced finaly, arghhhhh it was a :censored: pain in the :censored: :censored: :mad2: the old sensor had a metal case whereit goes through the hole, and had rusted to the blody thing!!! but its out now and the new one is in and working fine abs light out and abs cuts in when u slam em on so i took her for a spin through coundty roads and remberd just why i love her.....

 

BTW to help others out in the future, the resistance of the abs wheel sensors should be aproximatley 1,000 k,ohm Note: this figure will vary slightly depending on the ambient temprature.