Disconnecting ABS ECU?

[Jim Bowen 1]

Can i just disconnect the ABS ECU? (one in passenger front footwell). Since i've had the car the wire on top of brake fluid res has always been off and the light on dashboard has been disconnected too.

 

Lastnight i was turning around in a carpark and the ABS went mad, like it was like locking up and could hear the ABS vibrating etc also pedal went weird (didn't even have my foot on the brake pedal, i was driving forward at the time and was doing under 15mph) and the brakes sort of came on as if i was locking up. Stopped as soon as i put my foot on the brake pedal.

 

I never really use the ABS, never really lock up and a bit worried about it, so wonder if pulling the ABS ECU out will bypass the system and basically be non ABS? Does it work like that?

[paddy26 3]

the wire on top of the brake fluid reservoir is for the low brake fluid level sensor. It has nothing to do with the abs.

sounds like a sensor is gone on one of the front hubs or there is a damaged wire.

[Jim Bowen 1]

I was suspecting maybe the pedal position sensor, but just a random guess really. I did replace the two front sensors recently but did use gsf ones not VW ones. Never got round to testing the ABS out after that, just wanted it back on the road.

 

In the 6yrs and 70,000miles i've driven it has done it before, about 3yrs ago, but it really is once in a blue moon

[Supercharged 2]

Well worth checking it's not full of water!

[Jim Bowen 1]

I should have a look actually, had all that area apart to remove aircon and fit new foliage seal etc, might be leaking for all i know as never checked

[Stonejag 10]

I believe if you disconnect it then the light will stay on and you'll (obviously) have no ABS. Brakes will still work. Should have double-checked this while I had it out the other day but I forgot!

 

Once you've removed the three socket-head bolts holding it onto the side of the footwell, rotate the shiny metal catch up and back (in the direction of the harness) to unplug the connector all at once - the rocking arm makes sure you have it seated correctly and don't bend any pins as you remove it. Worth checking for corrosion on the pins if it's not obviously full of water, it's pretty exposed down there and the harness is huge!

 

Stone

[Jim Bowen 1]

not done it yet, but ABS come on again last night, loads of shaking etc then i have to put foot on brake to stop it and they come on really hard.

 

Have found it only happens with someone in the passenger seat, which is weird, and it seems to only happen at slow speeds like under 15mph i would guess.

[Jon_vr6 1]

Had it aswell turned out to be sensors and rear abs cages but you'll need vag com to confirm. Also if its getting to the point where its dangerous to drive it pull one of the abs sensor plugs off on the top front suspension turret abs light will permanently go stay on but you wont get any weird problems till you get it sorted

[Jonathan Claxton 10]

Its against the law to remove an abs system from a car that was fitted with it from standard, and an mot test station should fail it on an mot, i know we do at our test station as it is a clear fail, better to investigate the fault mate

[tonytiger 0]

Its against the law to remove an abs system from a car that was fitted with it from standard

Is it? I thought you could remove the system completely if you wanted to.

[Supercharged 2]

Is it? I thought you could remove the system completely if you wanted to.

 

No - must work if fitted originally.

[tonytiger 0]

When did that change? Have you got a link to info about it please?

[Jonathan Claxton 10]

Is it? I thought you could remove the system completely if you wanted to.

 

Nope, unless you can find a dodgy garage to pass it in mot, not a good idea tho

[tbvr6 0]

Do MOT stations maintain a database of cars that should have ABS fitted or do they look for existence of ABS pump? In other words, when testing, how do they know you have ABS fitted. I have an intermittent ABS light on situation, which looks like a minor pump valve issue and was wondering if I could just replace ABS light with blanking switch plate for MOT :-)

 

Tony

[tonytiger 0]

Any competent MOT tester should spot the abs pump I would have thought - not sure if there's a database/checklist though. Never seen my mot guy refer to one.

[Jonathan Claxton 10]

When you clock on for an mot they give you a print out sheet with things specific to that car, so if it was fitted with abs from standard it would say on this sheet and would tell you how long the light should come on for before going off, so if the light doesn't come on at all, and it says it should for 3-5 seconds then that would be a fail. As the bulb has obviously been removed.

[tonytiger 0]

Didn't realise that sheet was tailored to the car, thought it was just a standard sheet for all cars.

 

Going back to ABS removal, looking at this -> http://www.motuk.co.uk/manual_340.htm it says "If an ABS or ESC system has been intentionally rendered inoperative, the whole system must be removed. However, this does not apply to sensor rings or other ABS components which are an integral part of another component e.g. brake disc or drive shaft."

So does that not mean you can remove the abs system and pass the mot legally?

[Jonathan Claxton 10]

I don't know why it says that because it is clearly contradicted here

Check the presence and condition of all visible ABS and ESC system components.

 

Here

An ABS or ESC system component obviously missing or excessively damaged.

 

And here

does not illuminate

 

And as I work at a garage with an mot station I know we would fail it on that issue, which we have done before, and then it's a big job to rectify wonce removed