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E39 (1997 - 2003)
The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

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  #1  
Old 04-30-2010, 12:54 AM
freewilly freewilly is offline
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Help needed with ABS, ASC and Flat Tyre lights on yellow

Hi Folks,

I'm new here. I read a lot of posts about the ABS/ASC/DSC/Brake lights showing problem, but couldn't find anything so far that fits to my model. I have a 525i, E39, Year 2002. It has ASC but no DSC and a flat Tyre warning light instead the break light that is shown on most posts here.

When I bought the car (used) about 2-3 years ago, the yellow flat Tyre warning light was already on. The guy who sold it to me told me that he brought it to the official Beemer service point a few times and apparently they exchanged the wheel sensors but unfortunately to no avail. After a few times, he just gave up and accepted the yellow light in his panel. So did I. Obviously, resetting the warning light didn't help much neither.

A few weeks ago, the ABS and ASC warning lamps started to come on as well. First just intermittently, but now they're on almost all the time. Cruise control, Odometer etc. still work perfectly.



I started by taking off the ABS Connector and testing the pins. These were the result:

13-29:
Diode Test: It shows "1189" for a split second, then jumps to "1" and stays there
Ohm: 3.82MOhm

29-13:
Diode Test: 1*
Ohm: 2.42MOhm

30-31:
Diode Test: 1730 -> 1
Ohm: 3.82MOhm

31-30:
Diode Test: 1
Ohm: 2.45MOhm

28-12:
Diode Test: 1823 -> 1
Ohm: 3.86MOhm

12-28:
Diode Test: 1
Ohm: 2.44MOhm

15-16:
Diode Test: 1876 -> 1
Ohm: 3.86MOhm

16-15:
Diode Test: 1
Ohm: 2.48MOhm

* I have to remark that my Voltmeter does not show "OL" as described in most Forum Posts. I guess it displays "1" instead.

As all the 4 readings seemed similar, my guess was that the sensors are ok.
I anyway removed all four and checked them for dirt, cracks or other visible problems with the sensor and/or the blue connectors. There weren't any:

Front Sensor:


Rear Sensor:


I then proceeded to open the housing of the ABS control unit, which again looked ok to me:





So it seems to me that I have to either rebuild my ABS CU or buy a new one.
However, in another post I saw that it is possible to confuse the Tyre pressure warning and/or the ABS system by just using different Tyre threads in front and back Tyres! So back to my car I went to check them out and lo and behold, they were different:

Front: Falken FK 452 225/55ZR16 95W
Rear: Falken ZIEX ZE912 225/55R16 95V


So my question is, do you guys think that difference could be the culprit to confuse my ABS or is there anything else I should check?

Thanks a lot for your assistance!
Best,
Marc from Switzerland)

Last edited by freewilly; 05-04-2010 at 10:09 PM.
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  #2  
Old 05-02-2010, 10:18 AM
freewilly freewilly is offline
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nobody? :'-(
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  #3  
Old 05-02-2010, 10:29 PM
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bluebee bluebee is offline
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I, for one, saw this when you posted ... but my 2002 E39 has DSC (not ASC) and no "yellow flat Tyre warning light" ... so I stayed away ... not knowing your vehicle ...

The story about the "official" service (btw, it's bimmer, not beemer) service not being able to fix the problem seems suspicious ... but who am I to say ...

The sensors do have six different tests but generally nobody goes past the one you already ran with the DMM in diode mode (although it's not clear to me you tested them in both directions in diode mode but you seem to know what you're doing so I won't question that)...

The whole "tyre" thing I can't help you with...

If you need to rebuild your ABS, this thread will be useful as it's reputedly a single resistance-welded steel alloy wire that comes untacked from its bond pad.

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  #4  
Old 05-03-2010, 03:33 AM
freewilly freewilly is offline
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Hi bluebee,

Thanks for your response, I appreciate!

I guess if nobody on the board ever had an ABS/ASC problem just because of different tyre threads it pretty much can be ruled out as a possible issue here...

What I'm still confused is that my Diode test doesn't show a steady voltage reading, but jumps from 1700-1900 (mVolts I guess) to "OL" in a split-second.
I am not sure whether that indicates a problem with my sensors, a problem with my multimeter or a problem with myself.
However, the fact that all four sensors show pretty much the same results indicate that the problem is probably either with the meter or myself who doesn't know how to operate it properly.

Alas, I guess I have no choice but to send my ABS CU to BBA...

Thanks again,
Marc
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  #5  
Old 05-03-2010, 06:59 AM
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bluebee bluebee is offline
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Quote:
Originally Posted by freewilly View Post
my Diode test doesn't show a steady voltage reading, but jumps from 1700-1900 (mVolts I guess) to "OL" in a split-second.
I had read at your description and looked at your results when you first posted and figured you sounded like you knew what you were doing. In fact, I even cross referenced your pictures which are the best so far user submitted of the sensors.

One thing you might do is borrow another DMM but I'm just fishing with that answer (that's why I didn't answer the first time) as you seem more competent than most on this problem. Another thing, which isn't easy, I know, is to ask a friend if you can swap ABS control modules for a few days (I wouldn't let you do it to me so I understand this is harder than it sounds).

I do understand your frustration though of not being able to diagnose right down to the correct part. Nothing annoys me more than having to repair a part w/o KNOWING for sure (by my own tests) that it is bad. In fact, that is the reason it took me nearly a year to finally conclude that my ABS couldn't be isolated as the problem - but everyone here was actually dead on right that it was the problem - and $150 later, everything is fine.

So, I do sympathize with you that you need an answer ... let's hope some of the more knowledgeable people here have experience on your issue.
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  #6  
Old 05-04-2010, 07:58 AM
freewilly freewilly is offline
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Ok, thanks again bluebee! Here by the way a pic of my dashboard with flat tyre warning in the right corner:


Last edited by freewilly; 05-04-2010 at 10:07 PM.
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  #7  
Old 05-04-2010, 08:25 AM
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bluebee bluebee is offline
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Interestingly, you don't seem to have the "classic" ABS trifecta that we here in the states get (ABS, DSC, and BRAKE).

What we see is pictured below from this thread.

While I was looking up my ABS problem here, I do remember other people with ABS lights (maybe it was DSC lights?) that lit due to differently sized tires but I just searched and didn't see the threads I was looking for.

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  #8  
Old 05-04-2010, 06:30 PM
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540iman 540iman is offline
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Couple comments.. Your tires are the same size 225-55-16 The other numbers are irrelevant here.

The guy that sold it to you is likely a liar as no dealer would bother changing all the sensors when they know the module is the culprit most of the time. Changing one sensor..MAYBE, but all of them is pure BS.

I do not believe you VOM is diode test capable. You should be getting a forward VOLTAGE in one direction and none in the other direction. However, the resistance check is pretty good indicator as well and your sensors are fine.

Buy a module and enjoy a clear dash for once.
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  #9  
Old 05-04-2010, 07:38 PM
freewilly freewilly is offline
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I guess I will do that. I already contacted Jenny from BBA and she asked me to tell her the Bosch part# that can apparently be found on a sticker on the ABS CU. However, my CU doesn't have a sticker, at least not on the part that can be removed with the 6 screws. Any idea what I can do?
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  #10  
Old 05-04-2010, 08:16 PM
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540iman 540iman is offline
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sure..go to realoem for BMWs on the internet and enter your last 7 characters of your vin # and it will give you the part # your car used. Give me the last 7 (two letters and 5 numbers) and I will look it up for you if you have trouble navigating this very important site for BMW owners.
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  #11  
Old 05-04-2010, 09:02 PM
freewilly freewilly is offline
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Thanks 540iman, I appreciate!

I tried to figure it out on my own but not sure if I found the right part# as the picture looks different from my unit.
My 7 last digits of my VIN is GX99398. Could you kindly help me find the correct part#?

Thanks!
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  #12  
Old 05-04-2010, 10:19 PM
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bluebee bluebee is offline
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VIN=GX99398 --> 09/2002 E39 525i Sedan M54 Europe Right hand drive Automatic Production Code DT42 --> brakes --> control systems

At this point, for my USA-spec 2002 E39, I'd go to the HYDRO UNIT DSC/CONTROL UNIT/FASTENING but you said you have ASC so that leaves you with ASC HYDRO UNIT/CONTROL UNIT/SUPPORT.

Does your ABS control unit look like this?

BTW, it's confusing ... I think they accidentally swapped part numbers below ... what I "think" is your part number is 34526756343 ... but they have that labeled as part of "1" but it's described as "2".

So, it's confusing to me (someone please clarify???).
Bluebee


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  #13  
Old 05-04-2010, 10:25 PM
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bluebee bluebee is offline
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I looked at the circular hydraulic connectors in your picture and they don't look like that of the ASC unit pictured above.

Are you sure you have ASC?

If you have DSC (which is what I have on my 2002 E39), then this is your diagram and your ABS control unit part number is 34526769862.

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  #14  
Old 05-04-2010, 10:29 PM
freewilly freewilly is offline
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I went back and took the CU out again. Turns out I missed the sticker on the bottom. Apologies! My bad.
I guess according to the sticker, the number is 34526756342? Which wouldn't correspond to neither of the pictures above...
Hm, weird...


Last edited by freewilly; 05-04-2010 at 10:34 PM.
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  #15  
Old 05-04-2010, 10:34 PM
cn90 cn90 is offline
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I'd check the TPMS sensors +/- TPMS ECU first.
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  #16  
Old 05-04-2010, 10:36 PM
freewilly freewilly is offline
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Corresponds to this: Hmmm, the button on the middle console inside my car reads "ASC", that's why I thought I have only ASC...


No. Description Supplement Qty From Up To Part Number Price Notes
01 Hydro unit DSC 1 34516769536 $2,643.70
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  #17  
Old 05-04-2010, 10:49 PM
freewilly freewilly is offline
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Quote:
Originally Posted by cn90 View Post
I'd check the TPMS sensors +/- TPMS ECU first.
Interesting point, cn90! I always thought I have TPW only, which is measured by different rotational speeds from the speed sensors... How can I find out if I have TPW or TPMS and where is the TPMS ECU located? Thanks!
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  #18  
Old 05-05-2010, 08:14 AM
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bluebee bluebee is offline
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Quote:
Originally Posted by freewilly View Post
Hmmm, the button on the middle console inside my car reads "ASC", that's why I thought I have only ASC...
Dunno if this applies to European cars ...

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  #19  
Old 06-16-2010, 10:03 PM
freewilly freewilly is offline
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Ok, quick update: I uninstalled the ABS ECU and gave it to my wifey to bring to the US on her next trip for a refurbish by BBA Reman. Lo and behold, her luggage got stolen in Vegas with my dear ECU inside! What a bimmer, uh, bummer! So I was forced to buy a refurbished ECU from BBA Reman for 515 bucks incl shipping. I installed the refurbished one yesterday and took it for a ride. Everything seemed ok, all the lights off (and, so far, stayed off) except the flat tyre warning, which I think by now is due to the valve sensors that need to be replaced after 8 years. Also, I couldn't get the cruise control to turn on, but this morning I tried again, and somehow it decided to work this time. So everything is fine. Next step is to exchange those valve sensors to get rid of the flat tyre warning lamp.

Also, I read on some post that if you exchange the ABS ECU instead of refurbishing it, you have to reprogram it by your local Indy. Can someone clarify why this step is necessary and what happens if you don't? I didn't reprogram it and so far all seems well.
Oh, and I also didn't disconnect the battery as instructed on a piece of paper from BBA Reman. But some of the messages on this board stated not to do so. So I didnt... Cheers!
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  #20  
Old 10-08-2011, 06:19 AM
tborden tborden is offline
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And did your lights remain off

And have you ever had to have dealer re-code/program?

Thanks!

Tom
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  #21  
Old 10-08-2011, 02:20 PM
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bluebee bluebee is offline
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Originally Posted by tborden View Post
And have you ever had to have dealer re-code/program?
Good question.

If the OP responds, we should cross reference his answer here:
- What happens if you don't code your VIN into a new/salvage ABS control module (1)
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  #22  
Old 10-08-2011, 10:21 PM
freewilly freewilly is offline
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No never reprogrammed it and never had any issues
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