ASC/ABS lights illuminated today

[Kevlar]

While making a slow 90 degree right hand turn today... the ACS & ABS lights came on. I was just getting on the highway, so I ignored them for the time being. I cruised on the highway for a little while then proceeded to get off at my exit.

When coming to a stop... I turn the car off and restarted her. The lights went away. Odd...

Any body have any ideas? :dunno

[Rob Levinson]

A few things that might have caused it:

1) when was the last time you inspected your ABS sensors? As they are magnetic, a "beard" of metal dust from brake pad and rotor wear can develop and throw off the sensitivity. While you're in there, check the ABS rings on the hub for dirt or corrosion. Inspect all the teeth, as dirt in just one notch can trigger the fault.

2) related to number 1, a sharp turn is a large difference in relative wheel speeds, and a "slightly confused" sensor that works fine under normal circumstances can trigger a fault.

3) On a broader note, when was the last time you disconnected battery power and let the DME reset? There are some well-qualified BMW experts around who believe that a variety of things can cause the DME to start acting funky, resulting in all sorts of faults or problems, including simple things like a rough idle or occassional stumbling. Seems that a DME reset clears this out and the car will run better and other faults disappear. Sounds very similar to re-booting a Windows PC, doesn't it?

Hope this helps.

- Rob Levinson

[Kevlar]

I've never inspected my ABS sensors... I couldn't even tell ya what they are supposed to look like (new or old). I'll have to pull out the good 'ole bentley's manual... read it and see what I can do.

The battery in my car has never been disconnected (at least as long as I have had it -- 2+years). I'll have to try that... maybe that will help with my sleepy idle. Every now and then... for no reason at all, the car will "fall asleep" at a traffic light. I.E. I'll be sitting at the light... the car is idling fine. Then all of a sudden, I'll catch the DME sleeping. The idle will drop to about 250 the car will stumble... but they the RPMs come back up to 700 without me doing a thing... it's weird.

I'll try and check out those ABS sensors... maybe that's it. Thanks for the info.