Help! ABS/ASC/Traction Control Mysterious problem

[abdoul]

I have a 1999 740i with teh following diagnosed problems:

-- three ABS sensors were bad

I replaced all four sensors but am still having these problems:

-- ABS/BRAKE and AST symbol are lit permanently
-- Speedometer no longer works

EXCEPT

(1) when it's really cold in the morning (2) for about 10 miles or so then it dies.
-- occasional loss of power steering..

I had the system reset by my mechanic many many times.. but to no avail. I have 4 new abs sensors installed (properly.. cleaning before installing and what not...)

Where do I go from here

[toddbarry]

The speedometer issue would seem to point to a bad sensor, but it is extremely unlikely that multiple sensors (especially 3 or 4) are bad. In my case, the computer said a sensor was bad, but actually the control unit itself was defective. There is a repair kit available (about $800) if this is the case for you.

[KirtKoeller]

It is in fact the ABS/ASC/DSC control computer which is on the front of the ABS pump. Delt first hand with that and that is exactlly what it did.

[abdoul]

[abdoul]

That's mysterious! Whenever it's freezing outside... both speedometer and traction control works... ?!?!?

[BMW MAN]

[KirtKoeller]

I wish I had a good answer for that but I do not all I know is that was the problem with the car I had here and yes I pulled my hair out before I figured it out.

[abdoul]

Looks like I am buying a DSC/ASC controller.... Cheers

[Morty K.]

It is a very simple job to r&r the part. Then you must have the car re-programed.
Morty K.

[abdoul]

$499?? that's a lot cheaper than locally here... I'll check out Circle BMW.. :)

[genelevi]

shipping. Got it repaired and sent back to me. No reprogramming needed as I got my original module back. 5 year warranty. I couldn't be happier with the deal. Installation and removal was very simple.
Good luck!Gene
Jet Black '99 740i de-chromed

[zapperjoe]

It works when it's cold most likely because of a "cold solder joint" in control unit. Before I shelled out any money I would open up unit and investigate. Your looking for small rings/cracks in solder around the heavier components. Output transistors,relays etc..

[chanakya]

Hi Gene,

Can you please provide me the information of the workshop (contact, number, name address etc) who can rebuild he ABS module with 5 years warranty?

Thanks,

CB
cbhardwaj@gmail.com

[claudio512]

Instead or before rebuilding module check all four wires on wheels...
BTW, visual check is not enough... if replace one of the wires, must replace the others, too. CAVEAT: wires may appeared to be all right but the shield is weak and crack...




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