My '88 Sapphire has failed it's MOT due to the ABS light staying on.

We have replaced one of the sensors because it was giving a poor reading, that did not change anything.

We have also changed the ATE ABS ECU, still no change.

Anyone got any ideas of where to look next?

Cheers

 

Have you checked all sensors? Does the ABS light stay on all the time? Or does it go off and then come back on after driving a few meters?

My ABS light stayed on all the time and it was in deed the ABS ECU that was faulty. Maybe try another one?

 

Thanks Peter.

All sensors are giving the same/similar readings when you meter them out.

The light is staying on all the time, is does not go out when the car is driven.

I have already chnaged the ABS ECU - I suppose it could be another faulty one!

 

Carefully check the sensor rings, on mine one was rusted bad on the rear, such that a loose bit was bridging the gap between two segments, this caused the light to come on, but did go off after wire brushing up and driving around 500 metres, been fine since.
tabetha

 

Try the ''new" ECU 2 or 3 times ignition on/off

 

How does the pedal feel and does the brake servo work?

But if this was the case the light should go off after start and only come on once you've reached a certain speed (typically 5 - 10 mph).

 

I know what should be the case, all I can tell you is how mine acted, occasionally when it has been left a while it will come on whilst driving I stop and deplete the pressure in the system 3-4 times, then drive off once up to pressure again, light is still on but goes off sometime in the next 5 miles or so, seems to go off better if I stamp on the brakes a few times, when used daily as is normally there's no problem.
Even when the light was behaving I was still locking up the rear nearside wheel at high speed say 90+ in the wet, caused a few brown trouser moments!!
tabetha

 

My ABS light stays on all the time also, would I be right in thinking this is more likely to be the ABS ECU then? rather then one ofthe sensors.

 

Well if one of the sensor wires was completely broken, the light would stay on aswell. But this can easily be checked by measuring resistence. You can measure it directly at the ABS ECU plug (loom side) without getting dirty aswell!

 

Cheers

 

PM me if you need help with the pins.

 

I'm amazed you all still got your ABS bulb's in!

 

Cheers Peter

 

ABS on these cars is shit! It causes more harm than good IMO Most folks do away with it, might not admit to it right enough. If your MOT man is being anal about it there are ways to make the light behave as is should

 

doesnt sound like a sensor problem if its on all the time, my abs light was on for 4 years and passed mot every time, it wouldn't come on untill the car moved a few hundred yards, so never used to come on going in and out of the workshop, and if it did i blamed the brake rollers confusing the system!
That turned out to be a sensor, unless theres a broken wire somewhere? its a horrible system to try and find issues in!

 

Try cleaning all the plugs and check the wiring that goes to the pump/reservior. If the light only comes on when teh car moves its a sensor, if its always on its something else in the system at fault.

 

[quote=srgriffin;5084430]My '88 Sapphire has failed it's MOT due to the ABS light staying on.
Sensors and wire back ok.
Motor power up ok.
Brake level no power.
Above that the three plugs no power.
N/s brake block no power.
= wen test relay Green all cables power on ?
opened up found guts diloged,clipped then into seat .
ABS LIGHT OUT !! all good.
Just not a fuze check go abit deeper.
Pete 241

 

So what was the reason cause my light is on too, all the time.

 

Found my problem was a loose internals relay,powers up allo/s kit.
Pete

 

My abs light is on too permanently as well now.
Does anyone have the ecu PIN numbers so I can check the wring to them from the ecu plug end of the loom?

Cheers Paul