E39 speed sensor / abs issues!! help!

Good morning all (as I assume its AM now in the US?) ,

I'm coming here for help because i've not had much luck on the bmw UK forums and hopefully this should be something quite trivial, but I just dont have much experience with bmw's.

So basically I was driving along the other day and my DSC, ABS and (!) lights, all yellow decided to come on and stay on. So i put it on the code reader I have and the error said:

Left front wheel speed sensor

So i thought, no problem thats a piece of cake. Bought the part, put it on and started the car, the lights were gone. Great I thought. Not even 200 meters down the road, I could feel the abs and dsc kicking in and interrupting my ride, I speeded up a little bit, they tried to cut in again, then all 3 lights just stayed on.

So i did a bit of investigating. Read the codes and the code now said:

Left front wheel speed sensor OR ABS Inlet valve

So I took my old sensor and put it on the right hand side of my car, just to make sure it was actually buggered, and it was, because when i read the codes again it said 'Right wheel speed sensor cable'.

And just to make sure, I put the new sensor in the side which is already OK (drivers side), and the error was gone, so the new sensor is fine.

So my question is, having replaced the sensor and now have working sensors, is it really possible for the ABS module just to die? I am assuming that the 'ABS Inlet valve' message means the module. Even when I clear the codes and drive, the ABS/Traction control seem very confused and cut in randomly!!

Any help is MUCH appreciated!

Originally Posted by Adam540

my DSC, ABS and (!) lights, all yellow decided to come on and stay on. So i put it on the code reader I have and the error said:Left front wheel speed sensor

Most of us have already been down the same road you have, despite the fact you're driving on the wrong side.

The code readers are notorious for giving the WRONG readings when the ABS is involved. Almost all of us (including myself) have seen the wheel sensor implicated when it was the ABS control module all along.

There are six ways to test the wheel speed sensors, none of which involve the code reader, and the simplest of which entails a five-minute under-the-hood wheels-on-the-ground test with a digital multimeter.

Yes it's wholly possible and quite common for the ABS to "just fail". Most of us get a few days' warning with intermittencies but eventually all of us get the dreaded three-finger salute (brake, abs, and dsc lights).

I assume that's what you have. If so, then my advice is for you to read this thread, from start to finish ... which I'll summarize in the three steps below:

STEP 1: Do the 5-minute DMM test of the 4 wheel sensors; if more than one test bad, you're probably doing the test wrong; if any one tests bad, then go to the step 2; otherwise go to step 3.

STEP 2: If any one sensor tests bad, doublecheck at the wheel after cleaning them off and checking the wires visibly. If it tests bad, replace it and go back to test 1. If it tests good, then go to step 3.

STEP 3: Rebuild the ABS.

I cannot express my gratitude enough for your post, THANK YOU. I will get the ABS module rebuilt before returning the brand new sensor and test accordingly. I was almost certain it was the module.

If my old sensor turns out to be fine, i've saved myself £90!!

Thanks so much!

I have an update:

I sent my ABS module off to BBA-Reman (on ebay) and they were unable to fix the module. They were very helpful and gave me a full refund just to add, but they told me that the error was on the control board itself which is sealed with a tamper-proof substance which they cant get to.

So basically i'm looking at getting myself a new module it seems...

I have a question though. Is it a good idea to get an after-market wheel sensor ? or do these have a bad reputation?

Originally Posted by Adam540

Is it a good idea to get an after-market wheel sensor ? or do these have a bad reputation?

From what I've read here, you want as close to stock for the wheel sensors as humanly possible (check the threads as it's a common topic).

To give back to the bimmerfest community, it would be great if you post post mortem pictures of your opened up ABS control module, especially shots of the inaccessible circuit board area.

There have been reports of aftermarket DOA sensors. I suggest you check them with the VOM method.

If you need a new ABS module, we carry them. You'll just have to send me your shipping address for a quote.
https://eactuning.com/e39-e38-z8-abs...nit-p-426.html

Originally Posted by bluebee

From what I've read here, you want as close to stock for the wheel sensors as humanly possible (check the threads as it's a common topic).

To give back to the bimmerfest community, it would be great if you post post mortem pictures of your opened up ABS control module, especially shots of the inaccessible circuit board area.

I'll do that as soon as I get it back tomorrow.

Originally Posted by Jared@EACTuning

There have been reports of aftermarket DOA sensors. I suggest you check them with the VOM method.

If you need a new ABS module, we carry them. You'll just have to send me your shipping address for a quote.
https://eactuning.com/e39-e38-z8-abs...nit-p-426.html

I'm guessing you don't ship internationally? I'm based in the UK

Originally Posted by Adam540

I'm guessing you don't ship internationally? I'm based in the UK

We do, that's why I need your shipping address.

Thanks!

Gents - this info is very helpful...I have the DSC light on with airbag and an intermittent check engine. Code for check engine says camshaft position sensor - yet no starting problems. Replaced front camshaft sensor - no change. Can't seem to find any other codes - was thinking I would try replacing the DSC and ABS relays to see what happens...anybody tried that before replacing the module? Thanks!

Originally Posted by Ironnerd

Gents - this info is very helpful...I have the DSC light on with airbag and an intermittent check engine. Code for check engine says camshaft position sensor - yet no starting problems. Replaced front camshaft sensor - no change. Can't seem to find any other codes - was thinking I would try replacing the DSC and ABS relays to see what happens...anybody tried that before replacing the module? Thanks!

The camshaft sensor code is probably not related to your DSC light. What CPS do your codes point to? You replaced just one sensor, your other one may be bad.

Code reader didn't specify front or rear - my tech suggested the front as it is usually the culprit in his experience and is easiest to replace...guess I will replace the rear and see what happens. Thanks!

Any suggestions about the DSC light - no codes, but light is on along with airbag light...dealer wants $150 just to check, my indy tech says don't worry but it is the airbag light.

Originally Posted by Ironnerd

Code reader didn't specify front or rear - my tech suggested the front as it is usually the culprit in his experience and is easiest to replace...guess I will replace the rear and see what happens. Thanks!

Any suggestions about the DSC light - no codes, but light is on along with airbag light...dealer wants $150 just to check, my indy tech says don't worry but it is the airbag light.

Unfortunately your DSC could be from any of your wheel speed sensors or the module. I'd check all of your speed sensor with a VOM.

I got the two finger salute today (ASC, ABS light) and I was extremely P.O'ed. One of those times where in the last month Ive spent $3000 on a transmission rebuild, and after deciding I wasnt going to sell the car for a while I dumped another $4-500 into sensors, water pump and tension struts.

Anyway, thanks Bluebee for your very through post on ABS failure modes (link above). I suspect my steering angle sensor is on the way out. After reading your post I turned the wheel slowly lock to lock and the lights went out. I'lll let you know if it comes back.

Originally Posted by Flybot

I'lll let you know if it comes back.

Keep us informed!

One month followup on the intermittant ABS/ASC light.

I was initially getting the two mentioned lights and they would go out either at random, or sometimes if I turned the wheel from lock to lock. This degraded in to the transmission not automatically shifting in to 3 or 4. If this happens, you can manually shift up by clicking the shifter from D to 3 and back to D. Downshifting is still automatic. Anyway, I thought initially it was the steering angle sensor because it could sometimes get it to go away by turning the wheel. I wanted to do the diode check on the wheel speed sensors using Bluebees thread http://www.bimmerfest.com/forums/sho...1&postcount=48 but I have the older ABS System ('98 528) and the pin outs dont match up. I found this thread with the pin outs for the older ABS system: http://www.m3forum.net/m3forum/showthread.php?t=341672

Anyway, I changed out the left front sensor, which was literally crumbling apart. When tested, I got zero volts on the diode test and 3k ohms. It was supposd to be .5-2M ohms, according to the M3 thread. I cut the cable of the old sensor to do some further investigation and found that it had a small cut in the outer black insulation. The inner yellow/red wires were crumbling apart just touching them, and the copper was actually green from corrosion.

So as with all intermittent issues, it is fixed- until it isnt. The left front sensor was without a doubt bad, and I havnt had any errors since changing it out. I still dont see how the one sensor went from ABS/ASC error to then later include the transmission. Im keeping my fingers crossed.

This wheel speed sensor clearly gave its all and will receive full honors as it is laid to rest in the trash can.

Wires corroded 6" from the end of the sensor cable?


Crappy pic showing the wheel sensor and not showing the two bolt holes for attachment because they crumbled apart when removed??

Originally Posted by Flybot

One month followup on the intermittant ABS/ASC light.

I was initially getting the two mentioned lights and they would go out either at random, or sometimes if I turned the wheel from lock to lock. This degraded in to the transmission not automatically shifting in to 3 or 4. If this happens, you can manually shift up by clicking the shifter from D to 3. Downshifting is still automatic. Anyway, I thought initially it was the steering angle sensor because it could sometimes get it to go away by turning the wheel. I wanted to do the diode check on the wheel speed sensors using Bluebees thread http://www.bimmerfest.com/forums/sho...1&postcount=48 but I have the older ABS System ('98 528) and the pin outs dont match up. I found this thread with the pin outs for the older ABS system: http://www.m3forum.net/m3forum/showthread.php?t=341672

Anyway, I changed out the left front sensor, which was literally crumbling apart. When tested, I got zero volts on the diode test and 3k ohms. It was supposd to be .5-2M ohms, according to the M3 thread. I cut the cable of the old sensor to do some further investigation and found that it had a small cut in the outer black insulation. The inner yellow/red wires were crumbling apart just touching them, and the copper was actually green from corrosion.

So as with all intermittent issues, it is fixed- until it isnt. The left front sensor was without a doubt bad, and I havnt had any errors since changing it out. I still dont see how the one sensor went from ABS/ASC error to then later include the transmission. Im keeping my fingers crossed.

This wheel speed sensor clearly gave its all and will receive full honors as it is laid to rest in the trash can.

If you google you'll find out that many transmission issues are caused by wheel speed sensors. Transmission needs that sensor information to do the shifting, if the transmission is now shifting smootly there is no reason to worry.

^^^^ Im aware of that. What I was saying is, it doesnt make sense to me why the transmission issue came up after getting only the ABS/ASC light, and no other symptoms, for a few weeks.

Originally Posted by Flybot

One month followup on the intermittant ABS/ASC light

Oooh, fantastic!

Thank you for the followup - and - for taking the time to explain for others to benefit.
So that your information is fully leveraged, I updated post #645 of the canonical E39 ABS trifecta/bifecta thread with your wonderful information.

Regarding these two key troubleshooting documents below ... since they're for the E36, do we know where the E39 versions lie?

If not, can you help me re-title the upload link so that the E39 owners who can make use of them can benefit? That is, what E39 versions do the following two documents apply to?

Note: I had to split one due to the 7MB size limit.

Bluebee all I saw in those documents were wiring information, which can be found in WDS. WDS is a lot more user-friendly than those PDFs.

Originally Posted by HTK12

Bluebee all I saw in those documents were wiring information, which can be found in WDS. WDS is a lot more user-friendly than those PDFs.

Hmmm... OK. The thread that Flybot quoted had listed both of them as a reference for the pinouts - so that's why I included them (assuming they were important). I didn't actually 'read' them, as it's mostly gibberish to me - so thanks for taking a look at it for us.

I had the EXACT same problem as you, code reader said speed sensor, swapped then it said steering angle sensor, swapped it...then it said speed sensor again. I saw a pattern forming so I replaced the ABS module, problem solved!

BTW, someone PM'd me a few times today from the E38 side asking about the pinout on the older ABS control modules.

Here's the content of that PM exchange today, so that others may benefit from the effort.

I have recently bought BMW 1998 740iL Sedan E38. I have problems with ABS Module & Wheel Sensor. I read your post http://www.bimmerfest.com/forums/sho...1&postcount=48 but I have different ABS Connector it has 15 holes. Where can I find which hole are for which wheel sensor? I don't know which connector should I test. one connected to ABS? or one behind glove box (ABS/ASC computer connector) describe in http://www.bimmerfest.com/forums/sho...&postcount=645. My model is E38 I hope if I will take glove box out it wont turn out there are different connections.

here is how my connector looks like:

My answer was as follows:

I think everything you need is already in the referenced thread.
Remember, 200,000 people (views anyway) have visited that thread, and there are about 650 posts - all containing great information and lots of photos and diagrams.
So - by now - almost all the possible questions have been asked and answered already.
For example, this is the same 15-pin connector you have which was already shown long ago in post #498
http://www.bimmerfest.com/forums/sho...&postcount=498


But more importantly, you should scroll to post #333 which shows in detail the right connectors for your style of ABS control module setup:
http://www.bimmerfest.com/forums/sho...&postcount=333



More information is in post 341
http://www.bimmerfest.com/forums/sho...&postcount=341

And, more information is in the next half dozen posts after that.

Hope this helps but it's best to post your question to the forum and not in a PM simply because that will help others also.
Good luck.

I'll "spoon-feed" you to save you much reading. Do not replace anything else except your module. Or, you can try getting it rebuilt by BBA here in US. Re-build saves you having to recode, but do not lose sight of the age of your module which means it has greater chance of another connection failing. There was a post here showing how a module is re-built and believe company was in UK. They seem to replace all wires and resolder and not just the offending connection. Your module would then be as good as new practically.

Originally Posted by 540iman

I'll "spoon-feed" you to save you much reading. Do not replace anything else except your module. Or, you can try getting it rebuilt by BBA here in US. Re-build saves you having to recode, but do not lose sight of the age of your module which means it has greater chance of another connection failing. There was a post here showing how a module is re-built and believe company was in UK. They seem to replace all wires and resolder and not just the offending connection. Your module would then be as good as new practically.

Are you saying the fix for all ABS/Traction Control issues is to replace the ABS module? Who are you directing this reply to?

Originally Posted by Flybot

Are you saying the fix for all ABS/Traction Control issues is to replace the ABS module? Who are you directing this reply to?

Not at all. Read my other threads. I'm just talking about your particular case. You really should read the wealth of information and then you would understand. I was just trying to short cut you to your solution. You should read and you would probably reach it on your own. Certain clues in what you described that's all.

From here I'm going to direct you to do your own homework. Shouldn't be giving you the answers.