failed mot on abs light not illuminating. found the prob on the circuit board on instrument panel, some idiot had cut the track, so i soldered it up, problem is the light stays on now so obviously a fault with abs system! my question is, will it fail re-test if the light stays on or am i gonna have to fork out to get a dealer to do a diagnostic? the car is a discovery

cheers chris

if it's illuminated all the time then yes it will fail as it signals there is a fault within the system.

Stick a timer into the light circuit to illuminate the light on start-up for a few seconds...

Alternatively there could be a serious problem with the brakes!

Cutting the track is an old car dealer trick to turn the light off , to sell the car.

I wouldn't risk it mate.

Cheers

Chris

Or link it to another light such as the alternator, oil pressure or Airbag light.

Untill you get time to get the ABS sorted of cause.....

do an emergency stop. do the brakes actually work in abs mode?


if you want to risk life and limb, ignore it and take it to a different mot centre that might not notice.....

atb

steve

wheel speed sensors are a prob on these motors if I remember correctly.

thanx for the feed back guys.
checked all wheel sensors (as far as i can anyway without correct equipment)
brakes work excellent stops on a dime but not in abs mode apparently when a fault is found by the ecu it shuts the system off so your running as if abs isnt fitted.
gonna go to landrover tomorrow and let them plug it in (£60 + vat) just for them to tell me whats wrong
cheers anyway chaps

You should get an ac voltage from the speed sensors. I think I was wrong in the speed sensor statement. I seem to recall that it was the exciter rings mate.

quote:

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Originally posted by omega 24 v6
You should get an ac voltage from the speed sensors. I think I was wrong in the speed sensor statement. I seem to recall that it was the exciter rings mate.

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Chris,
Is it a Series II (Td5) Disco?

I had a similar probelm on my Td5 Defender. Went for the first MOT, but failed due to the ABS light on. I was told that if a vehicle is fitted with ABS it MUST work to pass the MOT.

Took it to a Land Rover dealer and they plugged their diagnostic computer in which tells them there was a wheel sensor fault. They adjusted the sensor and cleared the fault. No probelm until braking from high speed, the light comes on again. Took it back, plugged in their machine. Changed the sensor this time, Fault went away, then came back. Meanwhile I contacted a brakes engineer at LR (I work at Ford) and he says this is a common problem with the earlier ABS units. It is actaully the sensors inside the ABS module/pump itself. There are two sensors either end of a shuttle valve. On start up the valve oscillates and triggers the two sensors. The engineer told me that it is a known fault for these sensors to fail. The light comes on when a sensor plausibility check fails. The ABS unit tells the ECU that the sensor is faulty - switch ABS off. Only solution is to change the ABS unit!!! IRO £1500

However, this is a known issue on the earlier builds (Defender & Disco) and there was a recall notice issued about 8 months ago (I think). If you have to have the ABS module changed, you may be able to claim it back, or make them pay for the work. I did!!

Let me know if it is a Series II and I'll try and dig out the info for you tomorrow.

HTH
James

[Edited on 2-10-2005 by Donners90]

[Edited on 2-10-2005 by Donners90]

it isnt the td5 (not got that much brass im affraid) its the 300series 2.5tdi

but all info is mucho recieved
cheers

I have never understood this MOT rule - when a car has ABS it was sometimes as an option. If the ABS stops working you get the same car as the one without ABS, but it won't pass the MOT, whereas someone who didn't pay extra to start with has a car which will pass. Strange

Can't see any info / service actions relating to brakes on 300tdi series discos.

Hope you get it sorted.

James

thanx for the help james much appreciated