ABS light. does it need re setting to clear it?

[lukec88]

My ABS light has been on for a while, so i plugged it in to a diagnostic machine to see what was causing the problem. it was the sensor to the OSF. it was snapped clean in two. i have since changed this to a new (but second hand) one from jim 320i and the light is still on. would this be because i havn't plugged the car back into a diagnostics machine and cleared any fault codes that would have been left from when it has been broken? or will there still be an existing problem? thanks luke

[e30topless]

silver relay in the glovebox is probably fooked, have you ever jump started it ?

[skipunda]

On a facelift isn't the ABS down near the abs pump area? I know the early ones were in the glovebox.

[lukec88]

yeah its been jump started recently. any more info on this silver relay? could be very helpful if you're right.

[e30topless]

On a facelift isn't the ABS down near the abs pump area? I know the early ones were in the glovebox.

later one's too Chris,
there's a mod on here somewhere that someone did that fixes it instead of replacing, I'm sure Brian will know

[lukec88]

http://www.e30zone.net/e30zonewiki/inde ... Of_Problem

just been reading this. mine is definitely in the catagory of sensor fault. turn key to first click. the light illuminates like it should. start the car and it goes off. then once i start moving the car it comes back on and stays on until i turn the car back off again. so at least i have a better idea of what to check now. sensors, relays and fuses...

[lukec88]

would there be anywhere open on a sunday i could buy some new silver relays from? been googling and it seems a pretty common fault when the light is on like mine is.

[skipunda]

Click to enlarge pic



it will have a silver cap on yours. I used a soldering iron but then I was only testing to get it through an MOT. Put the rear demister on when jumping a car.

[lukec88]

ok thanks il look in to this tomorrow. does it have to be soldered or is there any other way?

[skipunda]

I wouldn't recommend soldering it at all because if the thickness of that wire is larger as a result of solder then it may not blow soon enough. I just did it because I was confident just a little dab would be sufficient.

Put a post up in the wanted section with the part number on yours, there doesn't seem to be anything on ebay right now.

[lukec88]

can i not buy new? or is it a bmw specific relay? like could i go somewhere like halfords and buy one the same?

[Brianmoooore]

Are you sure the ABS sensor you replaced was for the correct side? They are different, and NOT interchangeable.
Silver 'relay': These were only fitted to early facelift cars, so yours might not even have one.
If the light comes on with ignition, goes off when you start the car, then comes back on when you move, the 'relay' (if you even have one), is NOT at fault.

[bss325i]

And '89 325i's do NOT have the silver relay.

A quick check would be to check the resistance of each sensor to try and find the faulty one.

The rear sensors plug into the main loom under the rear bench and the front ones are in the engine bay clipped to the chassis rail.

They are a white/beige round two pin connector.

Disconnect each one and with a meter, check the resistance and if one is open circuit or a very different reading to the others then thats the one with the fault.

If they all read the same then i would be looking at the trigger rings on the drive shafts and front hubs for damage or corrosion and if they are ok then i would be checking the wiring of the main loom between the sensor plugs and the ECU plug.

Process of elimination starting with the most likely cause.

[bss325i]

Oh, and you can delete fault memory from the ABS ECU as the is no memory storage.

[Brianmoooore]

'89 built 325's may not have the relay, but most on here date their cars by the registration date, which can be many months later.
Resistance check won't show up a sensor fitted on the wrong side, and since one has recently been changed, this is the first thing to determine.

[bss325i]

True, it won't show up one on the wrong side but he may still have a fault with one (wrong one replaced in the first place) and its quicker and easier to unplug the sensors and check them with a meter that to jack up car remove the wheels and remove sensors etc.

Start with simple checks first before diving in.

[lukec88]

I bought a pair of these. Going to change it to the spare one I have just to see if it makes any difference

[capri_rob]

Had a problem with the wiring on my ABS - DanThe fixed it and it put the light out - no resetting required

[Andyboy]

Osf? Make sure the coil lead is nowhere near the abs lead - too close and it will cause interference and bring on the abs light. Come across this twice now.

[lukec88]

i changed the sensor for the other one in the pair i bought. it had a different part number on it and the diamond shaped bit that pushes into the hole was facing a different angle to the one i took out. now the ABS light is out and i am happy. thanks to whoever suggested that the different sides are different.

[Brianmoooore]

I learnt this one as a result of another zoner's experiences a couple of years ago. I got him to put an AC voltmeter on the pins that connect to the sensors at the ABS ECU plug, and compare the outputs when driving along. This revealed that the voltage output from the rear sensors was several times that from the fronts, which eventually led to the discovery, that the two front sensors had been transposed, following a rebuild.
IIRC, a further complication with deciphering this particular case, was that the output from the front sensors, although very low, was occasionally enough for the ABS to work normally, making the fault look like an intermittent electrical one.

[lukec88]

well however you came about it, thankyou very much. it has helped me out a lot.