ABS and MOT?

MikeHunt79 · 2 Feb 2009 at 15:50

I've seen a few cars going cheap 2nd hand, and one I've seen has failed it's MOT due to an ABS fault.

Now, if I was to disconnect the light in the dash, or even remove the whole ABS system, would the car then pass? What's the legality of doing this and will I get problems with insurance?

I haven't even bought the car yet but I thought it would be best to know these things before buying...

LSPIII · 2 Feb 2009 at 15:52

MOT centres look up on a database to see if the car was shipped with ABS. If it was, then it is tested. Disconnecting the light isn't illegal but the car will still fail. At least that's how I understand it.

The Edge · 2 Feb 2009 at 15:53

If the ABS light doesn't do what it's supposed to it will fail it's MOT. I don't know why because it has nothing to do with the normal braking system but that's how it works.

If you take the bulb out they will notice there is no light. One cheat is to wire the light in series with the low oil light or battery light, but since the ABS light ususally stays on for a few seconds that will most likely be picked up too.

Lostkat · 2 Feb 2009 at 15:53

That's how I understand it too. If it has ABS, the light will come on with the ignition. If you've disconnected it, they'll know because the light won't come on.

Doran · 2 Feb 2009 at 16:19

Why on earth do you need working ABS to pass an MOT?

Does it have some effect on the brakes altogether?

Rilot · 2 Feb 2009 at 16:27

If it's fitted it must work.
This applies to many things. You don't have to have indicators but if they're there, they must work.

Clarkey · 2 Feb 2009 at 16:46

ABS is not tested on the MOT (ok, a silly light is though).

edit - ok some sources say it is, and that if the ABS light sequence when turning the ignition on isn't right then it will fail. I've seen a lot of MOT's done though and never seen the tester take any notice at all of the dash lights when turning on. Indeed the cars are usually driven into the bay and left with the engine running. I think you'd have to find a jobsworth tester to fail it on this, seemingly a few Soarer owners have run into such a problem, as they don't have an idiot light for the ABS.

Hawk Tuah · 2 Feb 2009 at 19:29

ABS isn't tested at an MOT. However if your car has an ABS warning light staying on, then that is a failure.

Hawk Tuah · 2 Feb 2009 at 19:31

LSPIII said:
MOT centres look up on a database to see if the car was shipped with ABS. If it was, then it is tested. Disconnecting the light isn't illegal but the car will still fail. At least that's how I understand it.

How would they test the ABS, take it outside and slam the brakes on?

If an ABS warning light is on, then one of the ABS sensors has probably gone. This means your ABS probably isn't working. Certainly a good thing to get fixed pretty quick, especially in this weather.

Dogbreath · 2 Feb 2009 at 19:37

Clarkey said:
ABS is not tested on the MOT (ok, a silly light is though).

edit - ok some sources say it is, and that if the ABS light sequence when turning the ignition on isn't right then it will fail. I've seen a lot of MOT's done though and never seen the tester take any notice at all of the dash lights when turning on.

They could have their licence revoked if this was noted by a VOSA inspector.

lordrobs · 2 Feb 2009 at 21:29

On a slightly related note if the car should have ABS and its disconnected or taken out I'd expect it to cause problems with insurance.

BigglesPiP · 2 Feb 2009 at 21:47

LSPIII said:
MOT centres look up on a database to see if the car was shipped with ABS. If it was, then it is tested. Disconnecting the light isn't illegal but the car will still fail. At least that's how I understand it.

No they don't.

They look up a chart on the wall which shows how each car indicates a fault with the ABS, if it has ABS.

BigglesPiP · 2 Feb 2009 at 21:48

Bug One said:
ABS isn't tested at an MOT. However if your car has an ABS warning light staying on, then that is a failure.

The wheels will often lock in the rollers if there is no ABS, but that's not what that particular test is looking for.

energy · 2 Feb 2009 at 23:46

I would suspect the system triggers on the brake rollers anyway (as one axle is stationary while the other is turning), making the inspector suspicious if you had a non working ABS, yet rigged the bulb up to light on startup.

BigglesPiP · 3 Feb 2009 at 00:19

energy said:
I would suspect the system triggers on the brake rollers anyway (as one axle is stationary while the other is turning), making the inspector suspicious if you had a non working ABS, yet rigged the bulb up to light on startup.

Interesting point, I don't know what the procedure would be. Father is on MSN, I shall ask.

BigglesPiP · 3 Feb 2009 at 00:25

the big orange said:
(00:19:01) I taste volts...: Have you ever seen someone rig their ABS light for an MOT?
(00:19:37) (A) the big orange: verry dificult
(00:20:30) (A) the big orange: it has to follow the corect sequence for the vehicule in question
(00:21:18) (A) the big orange: we have charts telling us exactly how it should behave for each car
(00:21:30) I taste volts...: The ABS part of the MOT is just checking that the system indicates it's working right? What do you do if the ABS thinks its working, but the brakes lock in the rollers?
(00:23:08) (A) the big orange: the brakes do lock in the rollers at least half of the wheels are showing no speed signal at the point of braking

There we go, if you can rig the light an MOT won't detect the fault. Even with ABS, the wheels will lock in the rollers. God help you if you sell the car and the new owner skids into a child though.

Scania · 3 Feb 2009 at 04:14

BigglesPiP said:
God help you if you sell the car and the new owner skids into a child though.

I'd imagine this would be difficult if not impossible to prove (if the seller was willing to lie through his teeth)

I got an old XR3i thorough its MOT by removing the ABS Bulb, no problem. - To be fair, the Mk3 Escort's SCS system was hardly up there with modern ABS systems.

Oakesy2001uk · 3 Feb 2009 at 07:43

surely fixing the abs sensor would be little more trouble? had this on mine, turned out to be a loose wire into the sensor, on zipper-clip sorted it. if you can diagnose it to one wheel by plugging in then its either the sensor or the wiring surely?

Firestar_3x · 3 Feb 2009 at 08:02

Oakesy2001uk said:
surely fixing the abs sensor would be little more trouble? had this on mine, turned out to be a loose wire into the sensor, on zipper-clip sorted it. if you can diagnose it to one wheel by plugging in then its either the sensor or the wiring surely?

Who's to say its a sensor, it could equally be the Pump / Controller all much more expensive to fix, but i agree you should fix the fault in the first place not rig the car so it passes.

MikeHunt79 · 3 Feb 2009 at 14:43

Cheers guys, I've done a little more research on the car, and found ABS is quite a common fault on that model, but it's usually a bad connection to the controller box.

I think it will be easier to fix the ABS as opposed to ripping the dash apart and start re-wiring bulbs... Assuming I get the car in the first place.

I'm surprised an MOT station has a chart of how the ABS works on each model of car tho, you learn a new thing everyday!