ABS pump fault????

[Daveproyoyoyo 10]

Hi Everyone,

 

Got bit of a problem and need some help. Around December last year my brakes started playing up. They basically lock on randomly and then stay on. If I turn off the car and on again, they magically go back to normal until I touch the brake pedal and then stay on again. I suspected the ABS pump may be dead and it being the middle of winter, I took it off the road until I could be bothered to do something about it i.e. now.

 

I've just done a fault code scan and it came up with the following:

Address 03: ABS Brakes Labels: 1H0-907-379.lbl

Part No: 1H0 907 379 E

Component: ABS/EDS TEVES 04

VCID: 316D78FBFB8463CA76-4A9C

10 Faults Found:

00274 - ABS Inlet Valve; Rear Left (N134)

35-00 - -

00273 - ABS Inlet Valve; Rear Right (N133)

35-00 - -

00279 - Differential Lock Valve 1 (N125)

35-00 - -

00532 - Supply Voltage B+

35-00 - -

00283 - ABS Wheel Speed Sensor; Front Left (G47)

35-00 - -

00285 - ABS Wheel Speed Sensor; Front Right (G45)

35-00 - -

00285 - ABS Wheel Speed Sensor; Front Right (G45)

16-00 - Signal Outside Specifications

00285 - ABS Wheel Speed Sensor; Front Right (G45)

04-00 - Mechanical Malfunction

00290 - ABS Wheel Speed Sensor; Rear Left (G46)

04-00 - Mechanical Malfunction

01276 - ABS Hydraulic Pump (V64)

16-00 - Signal Outside Specifications

 

So what I'm reading here is that the ABS pump and every wheel speed sensor has had it and all need replacing. Is the differential lock valve and supply voltage b+ to do with the ABS pump?

 

I've heard of a company called BBA Reman for refurbishing my pump although have read mixed reviews. Could anyone give me a bit of a guide on how to remove the pump? Do I need to drain all the brake fluid first?

 

I've also read a little about upgrading to a Teves 20 system from a later golf. Should I be more looking to do that instead? I really just want to get the old girl up and running again for the minimum amount of money and faff.

[Dox 23]

First of all the ABS pumps job is to release a locked brake, not lock them on.

 

I'd look at the brake servo, I've heard of passats filling up with rain water from blocked scuttle drains and locking on the brakes.

 

Scan, then clear codes. Drive the car then rescan for current faults. ABS fuses and relays are behind the glovebox, check they're clean of corrosion. ECU is in the passenger footwell behind a panel next to their left ankle, again check for corrosion on its multiplug.

 

EDIT, if the light is on the dash the ABS is disabled, if the brakes still lock on its definitely nothing to do with ABS its mechanical

Edited July 28, 2017 by Dox

[seanl82 23]

Just to throw another one into the mix, the brake pedal position sensor may be worth checking. Its the cylindrical thing attached to the servo, just below the reservoir. Its essentially just a variable resistor by use of a piston/shaft in the centre. Easy to remove (remove the circlip and pull hard to break the vacuum), then test resistance with a multimeter when pushing in the shaft.

[Daveproyoyoyo 10]

Right, so I've cleared the fault codes and taken the car for a spin and the brakes didn't lock on once. I rescanned when I got back and it showed up with a front left ABS wheel speed sensor needs replacing.

 

I checked the scuttle drains and both were completely blocked so I cleared them out completely. If it was the servo, now it has dried out and won't get wet again have fixed the problem? Is there a way of checking it?

 

I've checked the ABS fuses and relays and the ECU, whilst some had minor corrosion most were good and the corrosion really was minimal.

 

I will check the pedal position sensor tomorrow.

 

I imagine the problem will probably come back knowing my Corrado. It loves to throw some "interesting" challenges my way just as I need it to be reliable. The problem was terrifying when you wanted to brake lightly and ended up doing an emergency stop on a motorway......

 

 

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[Dox 23]

If water was inside the servo it will still be there, the point I was making was a faulty servo could hold the brakes on (not that your servo was actually full of water like B5 Passats).

 

It sounds rather dangerous, I'd be tempted to leave the glovebox out so you can pull the fuses if needed.

 

Is the light still on the dash all the time?

[Daveproyoyoyo 10]

Ahh I see, I've never delved that deep into braking systems before. Noes the time to learn I guess.

 

The ABS light on the dash has been disabled and wired to the battery light by the looks of it.

 

At a loss what to investigate next really and am not inclined to take to a garage to "investigate" every possible cause of the problem whilst it shows no symptoms. I've done that in the past and ended up with huge bills and the same problems occur later on.

 

 

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[Dox 23]

The first thing I'd do is get the dash light working as it should, then you can see if the abs is disabled when the wheel locking occurs

[fendervg 33]

Good advice there to wire the warning lamp back up. Then clear all the faults in VCDS, take for a drive and re-scan. It could be a fault in the pump, but ABS is usually designed to fail open so that you retain mechanical braking in an emergency.

[Daveproyoyoyo 10]

Okay so a bit of an update. I have driven the car and the fault code came up with a failed wheel speed sensor which was replaced and now that code has gone but the problem remains and I'm at a loss.

 

The symptoms are when driving normally the pedal randomly will go very firm so you have to absolutely stamp on the pedal, then whilst still stamping it seems to suddenly completely free up the pedal presses down normally but obviously quickly due to still stamping, then when you go to take your foot off the pedal and continuing driving, the brakes are seized on. If I turn the car off and on again the pedal frees up and the car will drive normally for a little while before the same problem happening again.

 

 

 

 

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[georgaco 10]

Hi guys. VR6 '92 . Car was stationary under repair for +/- 2y. Now having rock hard brake pedal with abs light + handbrake light on. When turn ignition, the pump "clicks". I don't have mechanical experience myself and will take it to the garage, but have read a lot in the forums about the abs, and would like to give SOME guidance to the mechanic on where to start looking. Just bought a VAGCOM and got these codes:

 

VCDS-Lite Version: Release 1.2

Chassis Type: 50 - VW Corrado

Scan: 01,02,03,15,25

------------------------------------------------------------------------------

Address 03: ABS Brakes Labels: None

Controller: 535 907 379 E

Component: ABS + EDS

VCID: 253D7297ACF9

10 Faults Found:

00278 - ABS Main Valve (N105)

35-00 - -

00280 - Shareware Version. To Decode all DTCs

35-00 - Please Register/Activate

00279 - Shareware Version. To Decode all DTCs

35-00 - Please Register/Activate

00532 - Supply Voltage B+

35-00 - -

00285 - Shareware Version. To Decode all DTCs

35-00 - Please Register/Activate

00285 - Shareware Version. To Decode all DTCs

16-00 - Please Register/Activate

00290 - ABS Wheel Speed Sensor; Rear Left (G46)

16-00 - Signal Outside Specifications

00285 - Shareware Version. To Decode all DTCs

04-00 - Please Register/Activate

00290 - Shareware Version. To Decode all DTCs

04-00 - Please Register/Activate

00599 - Plausibility of Pressure/Brake Light Switch

04-00 - Mechanical Malfunction

 

Any clues from the above and from where to start?

The faults which are not shown due to the shareware version are real and must get a full version to diagnose them, or???...

Could the cause just/simply be the wheel sensor which shows a bad signal and therefore unlpugged or with a bad connection or something?

 

Appreciate some thoughts and guidance / Thanks

[1200 bandit 10]

Engine NOT running,pump the brake padel to evacuate the air from the servo the brake padel should be hard

With your foot on the brake padel start the engine and the brake padel should drop about 1 inch more or less.also check that the mechanism on the brake padel are not jamming,sized.

Check the servo pipe poss vavle sticking

I don't think the ABS fault will lock the brakes sounds more like a mechanical fault

[georgaco 10]

Engine NOT running,pump the brake padel to evacuate the air from the servo the brake padel should be hard

With your foot on the brake padel start the engine and the brake padel should drop about 1 inch more or less.also check that the mechanism on the brake padel are not jamming,sized.

Check the servo pipe poss vavle sticking

I don't think the ABS fault will lock the brakes sounds more like a mechanical fault

Thks 1200 bandit. Have already tried to depressurise the pedal but doesnt move an inch when starting the engine - pedal is constantly hard (brakes are not locked, but you have to press hard to brake). I think indeed it is a mechanical fault possibly with the servo, which wil check (or the abs pump itself, or the abs pressure valve, although i heard that it is quite rare that the pressure valve itself fails...). What about the faults of the wheel sensors and the voltage? Could these anyway appear if it is a mechanical/servo issue, or these can be other actual electrical faults? Need to still check the relays and eliminate them from the causes

[dr_mat 0]

The abs unit can and does fail from time to time. There was a link on a thread some time back with information about a firm that can refurbish them, or grab a used one off eBay.

But also do a hard power cycle to wipe the errors, bleed it fully (um, carefully, having pumped the ****e out of the pedal first) and bring it back up with a good battery so it can properly prime first.

 

 

A Corrado is for life, not just for the MOT.

[1200 bandit 10]

Thks 1200 bandit. Have already tried to depressurise the pedal but doesnt move an inch when starting the engine - pedal is constantly hard (brakes are not locked, but you have to press hard to brake). I think indeed it is a mechanical fault possibly with the servo, which wil check (or the abs pump itself, or the abs pressure valve, although i heard that it is quite rare that the pressure valve itself fails...). What about the faults of the wheel sensors and the voltage? Could these anyway appear if it is a mechanical/servo issue, or these can be other actual electrical faults? Need to still check the relays and eliminate them from the causes

I whoud go the fast and inexpensive way and go for a servo pipe, then servo,

The servo has water in it,the vavle inside the servo may jamming

[dr_mat 0]

Quicker, and cheaper...

 

http://www.ebay.co.uk/itm/222636443083

 

 

A Corrado is for life, not just for the MOT.

[a_riot 0]

The hard pedal you are experiencing is a complete lack of brake boost, so you end up with manual brakes. Good for the calf muscles but not safe. Corrados have brake boost as well as ABS but they are separate issues. You can still have power brakes without the ABS working, or you can have the hard pedal and no ABS as well. When either scenario happens, the ABS and sometimes Ebrake light will come on so I would fix the ABS light asap, since what can happen is that the pressure switch fails, and so the pump runs continuously thinking there is no pressure, and eventually burns out and you'll have no idea, since the only symptom is the ABS light coming on.

 

You should be able to hear the pump run when the key is turned to on for about 30 seconds, then turn off when full pressure has been achieved (relay clicks). If the pump doesn't stop running after 60 seconds, turn it off, and suspect the pressure switch has failed or its bore needs cleaning. If the coolant reservoir overflows, coolant can get into the bore and mess up the switch.

 

Its an Ate system, and they are well made, despite the perjoratives thrown at it by so many. The controller rarely fails, and I've even seen them completely immersed in water and still work once dried out. The accumulators and pressure switches fail, and I'd guess that's what's going on here. Both are fairly simple to replace if you can find new/used ones. The relays behind the dash also rarely fail, but they are easy to check.

 

 

 

This means that either there isn't enough hydraulic pressure in the accumulator to provide brake boost, or the system thinks that's the case and has disabled it. From what I've noticed the pump is pretty robust as long as you don't overheat it, its usually ok. Many of those DTCs are probably erroneous, triggered by something upstream, unless you've had the most horrible luck and had all four ABS wheel sensors fail simultaneously. You can also go through all the electrical steps in the manual but its not a fun task without the special tools. If you can at least get brake boost working, then you can fix the ABS at your leisure. For brake boost you need the pump, the accumulator and pressure switch to work. I'd also clean all connectors, check wiring, and check all the normal stuff that can go wrong on a 25 year old car.

[georgaco 10]

Thks guys. Checked and found 80% water in the brake fluid + the motor of the pump is dead. Have an old spare unit aside with a working motor (just tested it) and will try to replace the motor and see the result. (This unit used to be my old one which i replaced and i am afraid that the guy whi replaced it didnt bleed the system full/properly, because since the unit was replaced the car stayed at the bodyshop for 2 years....) The motor of the space unit might not work fully under pressure when installed (...) but will give it a try. If not, i am afraid will have to unavoidably go for unit rebuilt scenario, or switch to a more recent version (eg passat), or..... will revert for advise!!

[1200 bandit 10]

That will bring the brakes on ,as the water heats up it will expand and apply the brakes

[georgaco 10]

Pump seems to be dead therefore looking now for refurbishment. Ant other suggestions apart from BBA Reman?

[dr_mat 0]

And eBay..!

 

 

A Corrado is for life, not just for the MOT.