ABS problem 1999 BMW 735 iL automatic

abs
bmw

#1

ABS light comes on (plus two other lights) after 5 minutes drive in the morning, steering becomes hard (but not always) some other functions stop working e.g fuel gauge, KM counter, rev needle and speed indicator stop. What do I do? Change ABS controller or some other cheaper option is possible?
Car is running fine. Breaking made noise a few times.


#2

Sounds like the engine is stalling and potentially restarting or electrical disconnect going on.

ABS light is a symptom of the issue which is electrical or mechanical. The ABS may illuminate as it gets no signal as the other electrical items are failing.

Address the loss of power and I believe the ABS light will go out and cross your fingers will function properly. ABS except in rare case cause all the failures listed.


#3

AndrewRA - thanks for ur comment. I may have given incomplete picture in my post. The car keeps running perfectly when the lights come on. I am not sure I understand ur comment about STALLING but more important for me is WHAT TO DO?


#4

Go to a shop and pay to have the fault codes read out

Please post back

You can forget pep boys or autozone. They won’t be able to retrieve abs codes on a BMW

This is a wild guess, but you might have a voltage problem.

Undervoltage
Overvoltage
etc.


#5

I too suspect that your voltage is amiss, I’m guessing that it’s dropping to a low voltage at times. You probably have just enough to create a weak (likely erratic) spark on a warm engine, but not enough to keep the engine running strong when it’s loaded down by the power steering pump, and low enough to trip the ABS system warning light.

I agree with getting the codes read. I’ll suggest also having the charging system and the battery load checked.

One thing I absolutely recommend against is changing any parts without first doing diagnostics. You’ll waste a lot of time and money doing that.

Comment: the car is not running fine. Failure to feel erratic operation is not a reliable sign of proper operation when other signs of a problem are evident. If the car were running fine, we would not be having this conversation.


#6

You are about to find out how expensive BMW’s are to fix. This car may have variable effort power steering. It relies on sensors shared throughout the car on a CAN communications line. If the ABS has a sensor hard-wired to its ECU and that signal is shared over CAN to the power steering controller, maybe setting another or those lights. The loss may default to heavier steering. The ABS “made noise a few times” may indicate a failed or failing wheel speed sensor sensing a bad signal while braking causing the ABS to engage. This car also has stability control (DSC) that uses the ABS to prevent spins which is probably another one of those lights that you are seeing.

The best is to take it to an independent BMW specialty shop. You are about to find out why some people think BMW stands for Bring More Wampum (Native slang/slur for cash).

Good luck!