Abs light

[gingerrusta]

Hi guys

I have got the abs light on my dash and was wondering what it could be.
I have just replaced the wheel hubs on the front and also new pads and discs.
Could it be a sensor ?
Someone did say it could of been the abs ring on the back of the hub but this hasn’t made the light go out .

[gingerrusta]

Any ideas ??

[paultv]

Questions?

What year is your car?

Did the ABS work normally before you did the work on your car?

Have you jump started the car at all?



First test to see if the ABS system is at fault or one of the sensors.

If your lamp is on - then the bulb is good. Turn on ignition to position 1 and all your ignition lights should come on including the ABS light, keep an eye on the ABS light and turn the key and start the engine, if the light stays on and does not go out at all, then you have an ABS system fault.

If the light goes out briefly but comes on again when you move off, you have a sensor fault.

Paul

[paultv]

You obviously fixed your problem, what was it, it may help others with the same issue??

Paul

[gingerrusta]

Hi Paul
Sorry Car is 1988
Abs light has been on a while
Light goes on when ignition is on and goes off but then goes on again .
Sensor then you think ?

[gingerrusta]

Are the front and rear sensors the same ?

[Satan]

yep

[mark_i]

i have had this problem caused by the build up of dust and road dirt on the serrated ABS ring.
Cleaned the ring and sensor... sorted

[biffer]

Sensors on my '87 car are different -front ones are longer.

[gingerrusta]

I have got new hubs on front which has abs ring so I know they are 100%

[paultv]

Was this condition evident before the front hubs were changed?

If so I would first suspect the connectors between the sensors and the ABS unit - they are inboard of each front wing, and yellow. Carefully open and check for corrosion, clean with switch cleaner if you have it. The ABS is hugely sensitive to tiny changes in resistance -

You may well have a single rear sensor on the left hand side, the yellow connector is under the rear seat squab on the left side, the right side rear sensor same place but on the right if fitted.

Feel all the cables from sensor to plug to check for kinks or obvious damage - they are sensitive as hell, also if you have a multi meter, check each sensor at the yellow plug for about 1050 ohms.

Paul

[Malky320cab]

I have had the same issue and wasn’t sure there was sensors on the rear! Will check mines as it’s doing my head in as it didn’t do it when I got the car.

Like many E30’s there not shy of a jump start, what’s the implications of this as mentioned by Paul on the ABS? what should you check etc?

Cheers

[paultv]

There are voltage protection devices in the ABS, jump starting can blow them - in early cars it's a silver relay behind the glove box next to the ABS ecu. Later models there are two relays under the plastic cover of the ABS pump ( the silver one has the protection ) You can open and repair them, but probably a load easier to replace them.

Paul

[Malky320cab]

That’s worth a try cheers Paul

[gingerrusta]

Cheers guys will have a look at this .

[Brianmoooore]

Are the front and rear sensors the same ?

Rears are the same for each side, but the fronts are certainly not.
If you fit a front sensor on the wrong side, the actual sensor part will be at 90 degree to the sensor wheel and its signal output will be close to zero.

If the light comes on with ignition, out with engine start, and back on when the car moves, don't start messing with the surge protection relay, etc. The fault is definitely related to the sensors and their wiring, and playing with parts that can't be relevant just risks introducing faults that weren't there before!

[ChrisHC]

Probably not relevant to this fault but I have known the ABS light come on when running different size tyres on the front and back, because there is then a speed differential.