Mot failure Abs problem-no not a wheel sensor

[steve @ 0]

My abs light has been intermittently coming on and off over the last year. Over the last two weeks its mainly been off only for the swine to come on at its MOT test today .... u guessed it failure :( :(

Anyway all wheel sensors check out ok. Got the fault code:

 

00279 1223

 

Differential Lock Valve 1 -N125

 

Faulty wiring, wiring connection or valve coil.

 

Test wiring, wiring connections and valve coil

 

We had a quick look at the connection to the abs pump seemed fine gave it a quick clean but no better.

Has anyone encountered this error before (nothing of merit on the search). Bit stumped on the "valve coil" . Pretty fed up at the moment :(

[ADZ_VR6 0]

my abs lights on one of the rear sensors is cracked how do u test it, sorry i no that dont help u mate.

[Riley 0]

Its not the 2 pin connection on the master cylinder is it?

 

Neil. :)

[steve @ 0]

my abs lights on one of the rear sensors is cracked how do u test it, sorry i no that dont help u mate.

 

Use a multi meter to check the resistance of the sensor. The rears join under the back seats.

[steve @ 0]

Its not the 2 pin connection on the master cylinder is it?

 

Neil. :)

 

Umm possibly but not sure, thats the main problem.

[Supercharged 2]

Thats the Pedal Position sensor under the Master...

 

Steve - have you had any leaks recently (matrix / windscreen) and checked the ABS ECU for corrosion / water damage?

[steve @ 0]

I havent had any leaks since i ve owned it (2 years). I havent checked the ABS ecu yet, will have a look tonight. Surely if it was the abs ecu though would it not bring up another error code?

[Supercharged 2]

If the ECU's full of water it will do all worts of strange stuff!

[steve @ 0]

Just removed the plastic cover and the shelf above. Abs ecu looks bone dry (haven

[was8v 0]

I had a loose rear sensor cage. The error code related to sensor out of range or something like that, so its probably not that.

[steve @ 0]

Only reason I mentioned the rear rotors was due the discs and pads being replaced last year. The guy left one of the rears off, light came on, he refitted it and since then it

[steve @ 0]

Bloody thing hasn't come on all day! Going to book it in again for thurs afternoon, fingers crossed. ordered two new rear rotors as i know these were not replaced when the discs were. At least that will eliminate that from my search.

[ADZ_VR6 0]

my abs lights on one of the rear sensors is cracked how do u test it, sorry i no that dont help u mate.

 

Use a multi meter to check the resistance of the sensor. The rears join under the back seats.[/quote:61pnnwut]

 

 

What sort of resistance do you look for does it short out or open circuit if it its faulty?

[David Winter 0]

Before you do anything else remove your ecu and check the contacts. I was having exactly your problem. I had the codes read and it said the right hand sensor was duff but hey were new. So I cleaned them up again and had the code read again and it said the pump needed changing. This is such a pain to do that I thought Id look at the easy things first. The ecu is easy as to remove. Its easier than the relays to remove. You take off the kick panel between the pasenger door and the bulkhead. Four plastic bolts to undo and release the multiconector clip and the ecu should come out in your hand. Its about the size of a brick. Mine looked perfect until I looked at the contacts.They had mild corrosion on some of them and that was causing my problems. Cleaned the contacts and wd40 and no more problems! .Thank god I did not get the pump changed.! The only mistake I made was to source a replacement ABS/EDS ecu from a vw spares specialist before I removed mine but have not needed.

[steve @ 0]

my abs lights on one of the rear sensors is cracked how do u test it, sorry i no that dont help u mate.

 

Use a multi meter to check the resistance of the sensor. The rears join under the back seats.[/quote:1nlpan7e]

 

 

What sort of resistance do you look for does it short out or open circuit if it its faulty?[/quote:1nlpan7e]

 

I cant remember the exact values but you will be able to tell by comparing the others.

[steve @ 0]

Before you do anything else remove your ecu and check the contacts. I was having exactly your problem. I had the codes read and it said the right hand sensor was duff but hey were new. So I cleaned them up again and had the code read again and it said the pump needed changing. This is such a pain to do that I thought Id look at the easy things first. The ecu is easy as to remove. Its easier than the relays to remove. You take off the kick panel between the pasenger door and the bulkhead. Four plastic bolts to undo and release the multiconector clip and the ecu should come out in your hand. Its about the size of a brick. Mine looked perfect until I looked at the contacts.They had mild corrosion on some of them and that was causing my problems. Cleaned the contacts and wd40 and no more problems! .Thank god I did not get the pump changed.! The only mistake I made was to source a replacement ABS/EDS ecu from a vw spares specialist before I removed mine but have not needed.

 

Good call. Well the light has been off for 3 days now so took it back and it passed 8) . Not sure what the fault is/was but i'll check the abs ecu connection just to be sure.

[pete_griff 0]

hey buddy - one other thing i can think of is that when a rear bearing is on the way out, the play in the rear wheels can cause the light to come on intermittently, so you might want to check them - also if the sensors have a loads of swarf attached to them as they are magnetic (like my old ones did), this can send out odd readings as well - again probably not what the actual problem is oweing to the fact the fault code says wiring etc, but at least you could eliminate it from your list...

[Toad 0]

My abs is forked, the light doesn't come on (tried changing the bulb) and the pump doesn't fire up when the ignition is on. I did get codes saying that a couple of valves were knackered once, but haven't tried again.

 

Think I'm gonna try pulling the ecu apart over chrimbo, guess I can't break it any more than it already is. Lol.

[pete_griff 0]

sounds silly - but if you're getting nothing at all have you checked the fuses/relays - might be an easy fix save you ripping it all apart...

[Toad 0]

sounds silly - but if you're getting nothing at all have you checked the fuses/relays - might be an easy fix save you ripping it all apart...

 

Yeah, fuses and relays are fine, went through that all whilst I was keen. TBH the ABS is the least of the issues, but it would be nice to know that it could work if I wanted.

[pete_griff 0]

:lol: haha - fair enough. just remember that corrados are old and are now developing "quirks"! its all worth it in the end - just remember the grin that appears on your face when you go out for a drive in it "because you can" :D

[Skimask 0]

My abs light has been intermittently coming on and off over the last year. Over the last two weeks its mainly been off only for the swine to come on at its MOT test today .... u guessed it failure :( :(

Anyway all wheel sensors check out ok. Got the fault code:

 

00279 1223

 

Differential Lock Valve 1 -N125

 

Faulty wiring, wiring connection or valve coil.

 

Test wiring, wiring connections and valve coil

 

We had a quick look at the connection to the abs pump seemed fine gave it a quick clean but no better.

Has anyone encountered this error before (nothing of merit on the search). Bit stumped on the "valve coil" . Pretty fed up at the moment :(

 

How do youknow the wheel sensors are OK? If the resistance on each one is not 1.2KOhms then it is suspect.

 

Also there are 2 electrical connectors to the ABS pump - clean up the terminals on both.

Sounds like a dodgy wheel sensor.