Bimmerfest - BMW Forums - View Single Post - 2002 E39 ASC BRAKE ABS lights on => Diagnostic Procedure & Parts Location
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Old 06-16-2009, 11:21 AM
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bluebee bluebee is offline
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Location: San Jose, California
Join Date: Mar 2008
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Mein Auto: 02 BMW 525i M54 auto 130K
Originally Posted by 540iman View Post
You will always have that question of is an input to the module not there, or is it there and the module just can't sense it.
Hi 540iman,
I agree.

At this point, we're far past what most other people would have done:
- We've read every single bimmerfest post on the subject
- We've scoured the Internet for additional E39 Bosch 5.7 ABS troubleshooting advice
- We've combined all this and documented the entire procedure in a single post
- We've included everyone's advice that has been offered to date
- We've added plenty of E39 specific pictures (for the newbies, which I used to be just a month ago)
- We've answered everyone's questions as best we could (and we'll continue to ask questions)
- We've analyzed options and we've come to the same final conclusion as everyone else ...

In the end, I think you're right. Despite the fact that Carsoft 6.5 keeps reporting anything but the ABS control module, the anecdotal evidence seems to implicate the ABS module itself.

I have no problem with the money to rebuild my ABS module. I just don't think I'm done with the diagnostic steps yet. For example, I'm still not sure if I can GRACEFULLY take apart the ABS module to look inside and perhaps even to snap a few photos of it's inner working parts before sending it out to the rebuilders to fix.

At this point, I plan on:
a) Testing the brake pressure sensor (but I really don't expect it to be bad)
b) Give up on testing the "inlet valve, front left" (because it's inside the hydro unit)
c) Seeing if I can gracefully open up the ABS control module (for a living autopsy)
... and, after that ...
d) Sending it out for a rebuild (if I haven't destroyed it by opening it up first)

Meanwhile, I'll take almost all the advice given here and report back the results for others to benefit from who don't have to read hundreds of threads to get where we are today ... they can just print and read this one.

Has anyone here ever opened up their ABS module gracefully and then sent it out for a rebuild?

Does anyone know for sure the rebuilder will take it after I've dremeled off the cover?
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Last edited by bluebee; 06-16-2009 at 11:54 AM.
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