First serious post

unkel

Right. My '99 BMW 520i manual 2l petrol E39 had the ABS light lighting up, accompanied by the ASC light and at the same time neither speedo, odo or econo worked. This happened out of the blue one time and the issue has not disappeared.

After some internet research I reckoned the most likely cause was a failing ABS wheel speed sensor on the rear left side of the car. I procured one of them on ebay which my local mechanic fitted today and he reckoned the old sensor was deffo faulty. The ABS etc. light is still on. I haven't driven the car or tested if the ABS works though.

Here's my question: should the warning light have turned off after the new sensor was fitted or does the warning light only go off after you hook it up to diagnostics and switch it off that way?

Stoolbend

If the sensor was the only fault the light should go off once the car starts to move. A few metres should do it, but give it a couple of miles anyway.

If it doesn't go off after a spin you'll need to get it plugged in.

ronanc15

I know with Hondas and some other makes there is a very simple way to flash the ecu (pushing 2 prongs into a socket on the ecu). If this can be done with the BMWs it might be a better option to try that first before putting it on the diagnostics.

Slidey

Most ABS systems will reset once the car starts moving and the fault is no longer a 'current' fault.

You can always try disconnecting the battery for a few minutes. As I read your post my first thought was front LHS wheel as this is often the wheel that the speedo is taken from.

If the abs sensor can be adjusted closer to the sensor ring this may be the issue. The gap may be too large at the moment.

If not, the easiest thing to do is to find out if the fault code is definitely still on the LHS front. However it is not unheard of that the sensors have become mixed up before they get to the ECU, this means that the ECU thinks the front LHS when it is actually the RHS.

If they are 2 wire sensors a mulitmeter in the Ohm meter setting can tell you normally which one is faulty

Drummerboy08

Why did the speedo and associated clocks stop working too though? Surely the ABS sensor wouldnt have caused this?

Andrew33

Drummerboy08 wrote: »

Why did the speedo and associated clocks stop working too though? Surely the ABS sensor wouldnt have caused this?

The ABS sensors do a lot more than just measure braking performance, they are also used in the traction control, speedo, odo and even tyre pressure(by measuring wheel rotations, a soft tyre will rotate more to cover the same distance as a correctly inflated tyre).

I'd say drive it for a bit and see what happens.

Elessar

Without wanting to get off topic I have almost exactly the same problem. BMW E46 320ci, the ABS/ASC lights keep coming on and then going off again after a while. I know the systems work fine because I only used them in the recent snow apocalypse (they started acting up before this).

I'm thinking the sensor/s are dirty? Might be the same problem for you unkel.

RICARDO1982

I fitted a NSR ABS sensor to my friends E46 BMW 2000 model i did not have a diagnostics and the light went away in 2 days and did not return . See how you get on.

Myrddin

As above, usually driving a few meters will do it. Ive seen one or two picky cars where the light only went out after a drive cycle (start, drive, off).

Owen

Pity you're not in Cork, I'd reset it for you. But try disconnecting the battery for a while, and then try turning the traction off and on to see what happens.

Voodoomelon

unkel wrote: »

Right. My '99 BMW 520i manual 2l petrol E39 had the ABS light lighting up, accompanied by the ASC light and at the same time neither speedo, odo or econo worked. This happened out of the blue one time and the issue has not disappeared.

After some internet research I reckoned the most likely cause was a failing ABS wheel speed sensor on the rear left side of the car. I procured one of them on ebay which my local mechanic fitted today and he reckoned the old sensor was deffo faulty. The ABS etc. light is still on. I haven't driven the car or tested if the ABS works though.

Here's my question: should the warning light have turned off after the new sensor was fitted or does the warning light only go off after you hook it up to diagnostics and switch it off that way?

I have direct experience with this on my E38, an identical system. The car does not have to move, let alone drive a number of miles for the dash lights to turn off. All you have to do is replace the sensor, turn on the ignition to position 2 wait for all the lights to go out and within a few seconds the offending lights just blink off.

The fact that your lights have not extinguished means its a different ABS sensor more than likely. Front and back are not interchangeable, however you can move them from side to side to diagnose the faulty sensor; in this case you can try moving the new sensor to the rear right wheel (assuming you still have the old one). Does your E39 have cruise control? The rear right wheel controls the cruise control system and if you have that option and it still works, then you know its a front sensor.

Slidey

If you check the resistance of the sensors it is a good way of finding a faulty one.

Normally when they are shagged you will have either an open circuit or a low ohm reading.

AFAIR most sensors operate between 50 and 150 ohms. I am open to correction on this

unkel

Thanks everyone for the help and suggestions

barry81 wrote: »

If the sensor was the only fault the light should go off once the car starts to move. A few metres should do it, but give it a couple of miles anyway.

If it doesn't go off after a spin you'll need to get it plugged in.

My mechanic drove it for a mile. I haven't transferred insurance onto the car but once I will, I'll drive it for a bit and report back here. I've unplugged the battery for about 5 minutes but that made no difference.

Voodoomelon wrote: »

I have direct experience with this on my E38, an identical system. The car does not have to move, let alone drive a number of miles for the dash lights to turn off. All you have to do is replace the sensor, turn on the ignition to position 2 wait for all the lights to go out and within a few seconds the offending lights just blink off.

The fact that your lights have not extinguished means its a different ABS sensor more than likely. Front and back are not interchangeable, however you can move them from side to side to diagnose the faulty sensor; in this case you can try moving the new sensor to the rear right wheel (assuming you still have the old one). Does your E39 have cruise control? The rear right wheel controls the cruise control system and if you have that option and it still works, then you know its a front sensor.

I'm fearing you are right about that the new sensor should clear the light straight away. I've no cruise. I'm pretty sure that in the E39 the rear right speed sensor controls the cruise, and the rear left speed sensor controls the speedo. My car is of the earlier type with only the more basic ASC (and not DSC)

Slidey wrote: »

If you check the resistance of the sensors it is a good way of finding a faulty one.

Normally when they are shagged you will have either an open circuit or a low ohm reading.

Yes. But I've seen lots or reports of false positives of high impedance readings on the E39 with sensors that are ok - obviously I can't explain why

If the lights won't go off after driving it for a bit, I guess it is time for a diagnostic...

El Guapo!

I had a problem similar to this yesterday. (it was on a '06 320 though). The handbrake light was on (in yellow not red) and the traction control light was on. I put my diagnostic computer on it but it couldnt read the fault code:mad:
I noticed the front brake pads were fairly badly worn so I replaced them along with a new pad wear sensor. I knew it was a longshot but no harm in trying. Still the problem persisted.
I brought it to a guy I know in BMW and got him to put it on his computer.
Turns out the hydraulic control unit for the traction control and abs needs to be replaced.....to the tune of 2 grand just for the unit, with another 600-700 labour.:eek:
After he picked me up off the floor,... he said he'd stick in a good-will claim with BMW and see what happens. I should know by today or tommorrow.
OP hopefully this isnt your problem but just thought I'd put it out there in case anybody else encounters this problem.

mickdw

Dean09 wrote: »

I had a problem similar to this yesterday. (it was on a '06 320 though). The handbrake light was on (in yellow not red) and the traction control light was on. I put my diagnostic computer on it but it couldnt read the fault code:mad:
I noticed the front brake pads were fairly badly worn so I replaced them along with a new pad wear sensor. I knew it was a longshot but no harm in trying. Still the problem persisted.
I brought it to a guy I know in BMW and got him to put it on his computer.
Turns out the hydraulic control unit for the traction control and abs needs to be replaced.....to the tune of 2 grand just for the unit, with another 600-700 labour.:eek:
After he picked me up off the floor,... he said he'd stick in a good-will claim with BMW and see what happens. I should know by today or tommorrow.
OP hopefully this isnt your problem but just thought I'd put it out there in case anybody else encounters this problem.

This is the most common fault on 3 series of that age. BMW are pretty much giving the part free in all cases. They will look for the labour though which is crap enough seeing as the parts are probably costing them F all from their supplier seeing as they appear to be faulty from new.

El Guapo!

mickdw wrote: »

This is the most common fault on 3 series of that age. BMW are pretty much giving the part free in all cases. They will look for the labour though which is crap enough seeing as the parts are probably costing them F all from their supplier seeing as they appear to be faulty from new.

Yeah I've heard of this happening on a few cars now since I came accross it the other day. BMW should just bite the bullet and issue a recall on all affected models. Its this type of thing that may cause customers to lose confidence in them and may ultimately cost them more money in the long-run.
On a side note I still haven't heard back yet about the good-will claim.

OP any luck with your problem yet?

Elessar

To update my last post, my speedometer now isn't working either. Same as you unkel.

My car is due in for a service soon, are the ABS sensors expensive to replace?

Fishtits

unkel wrote: »

My car is of the earlier type with only the more basic ASC (and not DSC)

Just a heads up on this, AFAIK all E39's from build date 9/99 had DSC III.

Regardless of whether ASC or DSC was on the disarm button.

ASC had the module at the glove box, DSC module is coupled with the ABS unit in the engine bay.

-useless information- if you keep the disable button pressed for 10 seconds, the warning lamp will extinguish and you will have DSC/ASC but no traction control. It resets on the next start up.

Buford T Justice

Elessar wrote: »

My car is due in for a service soon, are the ABS sensors expensive to replace?

That all depends on if you plan on doing this yourself or getting a garage to do it.

You can get sensors online like here and change it yourself, but expect to pay at least €70 at the dealer just for the part alone, there'd be an hour labor on it anyway.

If you do buy it online though, be absolutely sure that you're getting the same part that you are replacing, most sales on ebay will say the models the parts support.

I did it the online way and it worked out very well for me. I had no problems, but i had no issues changing it myself:D

Mr.David

I presume that on the 3 series, the ABS works the same way as I am familiar with on Jags i.e. there is a casselated ring on the driveshaft and the sensor positioned a couple of mm above the ring. It basically gets a pulse signal when from each of the teeth on the casselated ring as the driveshaft rotates.

This signal is then used to determine wheel speed, wheel slip (i.e for ABS & traction control) etc etc etc and due to so many interlinked systems nowadays, one such faulty signal can cause a raft of systems to kick up.

Try getting a toothbrush and cleaning out the casselated ring, sometimes the gaps between the teeth can get built up with bits of crap causing a faulty reading from the sensor even though its not the sensor that is at fault.

Worth a try anyway

unkel

Update: it turns out to be a bit more complicated. Specialist diagnostic company hooked it up today and say there's no communications at all with the ABS module through OBD2. I've booked it in with them for next week - will let you know the results.

unkel

Fishtits wrote: »

Just a heads up on this, AFAIK all E39's from build date 9/99 had DSC III.

Car was registered in August '99, so it has definitely ASC!

listermint

This reminds me of this post over the road..

http://www.bmw-driver.net/forum/showthread.php?t=14048

May be of use.

Slidey

Jesus, I don't mind spending money on parts when it fixes the problem but that would have me driven mental

listermint

Slidey wrote: »

Jesus, I don't mind spending money on parts when it fixes the problem but that would have me driven mental

Tell me about it, Driven around in circles (excuse the pun)

Voodoomelon

listermint wrote: »

This reminds me of this post over the road..

http://www.bmw-driver.net/forum/showthread.php?t=14048

May be of use.

Reminds me of when I tried to get a rear ABS sensor out and did the same thing as him, snapped the damn thing in half and had to drill it out. Nightmare job.

rebel.ranter

I have seen this exact thing happen on another e39. It is very likely to be the rear left wheel sensor. That is what fixed the problem on the one I saw.
Before we replaced it I reset the fault codes but they came back straight away without the car moving. The sensor is a hall sensor using similar principle (hall effect) to a parking sensor. It just fails.

Here is a discussion on the exact problem:
http://bimmer.roadfly.com/bmw/forums/e39/8798080-1.html

Elessar

My car is due in to AC cars this week with an identical problem. Speedo has stopped working altogether now too. Definitely a speed sensor. Quoted 200 euro give or take to replace! On top of an inspection service for 350! Gulp!

unkel

rebel.ranter wrote: »

I have seen this exact thing happen on another e39. It is very likely to be the rear left wheel sensor.

That's what I thought

Very very likely to be the rear left wheel sensor (I would have given it a 90% chance of being the problem). That's why I cheaply sourced a sensor and had my mechanic fit it. But the rear left wheel speed sensor wasn't the problem

Voodoomelon wrote: »

Reminds me of when I tried to get a rear ABS sensor out and did the same thing as him, snapped the damn thing in half and had to drill it out. Nightmare job.

Yup same thing happened to my mechanic.

unkel

Sorted.

It was indeed the left rear wheel speed sensor. My method of google-diagnostics worked

But the part I sourced on ebay was not quite right (probably BMW used a different sensor in the late '99 an onwards model?) And my local mechanic made a balls fitting it (cause obviously it didn't fit). Expensive lesson

You get sorted too, Elssar?

Elessar

unkel wrote: »

Sorted.

It was indeed the left rear wheel speed sensor. My method of google-diagnostics worked

But the part I sourced on ebay was not quite right (probably BMW used a different sensor in the late '99 an onwards model?) And my local mechanic made a balls fitting it (cause obviously it didn't fit). Expensive lesson

You get sorted too, Elssar?

Yeah got it all sorted in the end. It was the left wheel speed sensor aswell. All is working now!