ABS light wont work

mugpunter1970

Hello,

I have an 04 Focus up for mot in a few weeks but cannot get the ABS light to work for the 4 second check when the ignition is turned on.

Tried 3 different clocks, so its not the bulb, ran diagnostics didnt detect any faults.

Fuses are all ok, ABS actually works, but even when i disabled one of the wheel sensors light still didnt come on.

Should I be looking for a worn wire, or what should I be looking for?

Stooby2

You may need to trace the wire from the bulb back to the ABS ECU to make sure it's not broken. If there's no obvious damage then a continuity check would be the next step.
Checking the earth from the clocks is worthwhile. Check the connector pin and socket to the ECU is clean. If you still get no joy, then you may need to swap the ECU.

scaredofdebt

Is that definitely an MOT fail?

Surely the test should be if the ABS actually works, how silly if not.

Iceweasel

scaredofdebt wrote: »

Is that definitely an MOT fail?

Surely the test should be if the ABS actually works, how silly if not.

Yes it's a definite fail.

It fails as it does not function as it should.

And I don't think it's silly at all.

It's a check system light which is telling you that there is something wrong.

What might be considered silly is that the tester does NOT actually test that the ABS is working!

They only check for missing components and their condition.

The warning light is relied on to indicate malfunctions of any part of the system including the warning light itself, by it's self test sequence.

The OP's warning light indicates that.

http://www.transportoffice.gov.uk/crt/doitonline/bl/mottestingmanualsandguides/mottestingmanualsandguides.htm

Retrogamer

scaredofdebt wrote: »

Is that definitely an MOT fail?

Surely the test should be if the ABS actually works, how silly if not.

Yes, it's definitely an MOT fail.

The light comes on for a few seconds usually when you turn on the ignition. The light comes on to let you know the ABS is doing a self check.
If the light goes off again, then the self check passed and all is ok.
If it stays on then it's used to alert people there is a fault.

There is no other way an MOT inspector can check the ABS is working as it should be. As it should be is the key word. You can have ABS working, but not working as it should.

Too many people used to remove the bulb to get cars with faulty ABS to pass the MOT so now if the bulb doesn't iluminate it's a fail (unless you remove all the ABS components from the car - sensors & pump being the main stuff)

mugpunter1970

Is it possible that changing the clocks has left the abs system needing reprogrammed? Or would that only need done if the ECU was changed?

Westmead_Fan

can someone please tell me where it is a failure.

if the lights on = fail
if the light does not light up = pass & advise

mrmechanic

Westmead_Fan wrote: »

can someone please tell me where it is a failure.

if the lights on = fail
if the light does not light up = pass & advise

deffinately a fail, not pass and advise.
There you go, down right hand side
http://www.motinfo.gov.uk/htdocs/m4s03000401.htm

mrmot

Westmead_Fan wrote: »

can someone please tell me where it is a failure.

if the lights on = fail
if the light does not light up = pass & advise

That's for airbag lights.

The ABS lamp no longer has to follow a set sequence, but it must work.

MOT testers manual section 3.4

Method of inspection:
If the vehicle is fitted with an ABS and/or ESC system, check that the relevant warning lamp(s): a. is fitted b. illuminates c. does not indicate a fault

Reason for rejection
1. A warning lamp: a. is missing b. does not illuminate c. indicates a fault

Westmead_Fan

mrmot wrote: »

That's for airbag lights.

The ABS lamp no longer has to follow a set sequence, but it must work.

MOT testers manual section 3.4

Method of inspection:
If the vehicle is fitted with an ABS and/or ESC system, check that the relevant warning lamp(s): a. is fitted b. illuminates c. does not indicate a fault

Reason for rejection
1. A warning lamp: a. is missing b. does not illuminate c. indicates a fault

my bad, i was thinking airbag light

Stooby2

Retrogamer wrote: »

Yes, it's definitely an MOT fail.

The light comes on for a few seconds usually when you turn on the ignition. The light comes on to let you know the ABS is doing a self check.
If the light goes off again, then the self check passed and all is ok.
If it stays on then it's used to alert people there is a fault.

That's only partly correct - most modern ABS systems need the car to be driven a few metres so the ECU detects a signal from each wheel sensor - and then turns the light off.