ASC/ABS light on?

[FromSVTtoM3]

While driving into work tonight my ASC/ABS lights came on. About a month ago I was experiencing significant steering wheel vibrations after 5-10 minutes of highway driving. I took my car into the shop and they determined that the front brake calipers were going bad causing the brakes to stick. They replaced the front brake calipers, rotors and pads. I'm currently running Hawk HP+ pads in the front and HPS pads in the rear. I expect that the HP+ will transmit some noise and dust quite a bit, but lately the have been getting extremely noisy. They sound like more of a metal on metal scraping than a normal brake pad squeal. I also had new front control arms,tie rods and poly control arms bushings put on a couple weeks ago. I don't know whether or not that would have any bearing on the brakes or not. Tonight is the first time the ASC and ABS lights have came on.

Any ideas as to what is causing this?

[egebhardt]

The ABS light can come on because of detection of slightly different rotational speeds of 2 wheels. The wheels could spin at different rates if they had different diameters, say from a different brand tire, but not the case for you.
Maybe if one brake was holding the wheel, over time it might result in less speed relative to the other.
Perhaps a bad sensor is reporting less speed than another.
Any changes to the back end that might result in different wheel spin rates?

[FromSVTtoM3]

I actually changed the control arms/bushings/tie rods because I noticed the car had a tendency to wander a bit on bumpy sections of the highway. I'm running slightly larger tires up front(235/45/17) and stock 245s in the rear all of which are Star Specs. I'm wondering if it's possible that one of the calipers is still sticking and causing the tug and ABS light to activate.

There aren't any recent changes to the back end that I am aware of. It has the stock diff/ratio. The bushings and mounts and basic suspension components in the rear have just about all been refreshed since I purchased the car 2+ years ago. When I put the start specs on I did notice that the ASC light was coming on and intervening on WOT highway pulls from 3rd/4th gear at times. I don't recall it doing that when I had my Yokohama Advan S4's on the car.

[Stuntman]

While driving into work tonight my ASC/ABS lights came on. About a month ago I was experiencing significant steering wheel vibrations after 5-10 minutes of highway driving. I took my car into the shop and they determined that the front brake calipers were going bad causing the brakes to stick. They replaced the front brake calipers, rotors and pads. I'm currently running Hawk HP+ pads in the front and HPS pads in the rear. I expect that the HP+ will transmit some noise and dust quite a bit, but lately the have been getting extremely noisy. They sound like more of a metal on metal scraping than a normal brake pad squeal. I also had new front control arms,tie rods and poly control arms bushings put on a couple weeks ago. I don't know whether or not that would have any bearing on the brakes or not. Tonight is the first time the ASC and ABS lights have came on.

Any ideas as to what is causing this?I had to replace my LF caliper and rebuild my RF last week for the exact same reason.

In regards to the lights. Do a search, it is very common for our cars to have the ABS/ASC lights come on randomly. I'm still not really clear what the cause is myself because I did clean my ABS sensors (which had a lot of metal dust on them from my semi-metallic pads) but the lights still come on randomly. For me, the light seems to come on when it's really hot outside (95*+) but not on cool days.

In regards to the scraping. How many miles have you put on the brakes since you had the new pads put on? Did you do a proper bed-in procedure?

[FromSVTtoM3]

I had to replace my LF caliper and rebuild my RF last week for the exact same reason.

In regards to the lights. Do a search, it is very common for our cars to have the ABS/ASC lights come on randomly. I'm still not really clear what the cause is myself because I did clean my ABS sensors (which had a lot of metal dust on them from my semi-metallic pads) but the lights still come on randomly. For me, the light seems to come on when it's really hot outside (95*+) but not on cool days.

In regards to the scraping. How many miles have you put on the brakes since you had the new pads put on? Did you do a proper bed-in procedure?

I would say that I put roughly 1,000 daily driven miles on the brakes with 100 of those miles being track miles. I did a PDX at Mid Ohio back in late July and the brakes were much quieter afterwards. About a week and a half after getting back the brake squeal started to return. I am now in full dump truck/school bus mode....:mad I followed the recommended break in procedures for the pads after I initially got them. I may try to go back out and bed them in again, but at this point I will likely switch the fronts back to HPS. I could keep the HP+ and put them on before I hit any more road courses.

[Stuntman]

I would say that I put roughly 1,000 daily driven miles on the brakes with 100 of those miles being track miles. I did a PDX at Mid Ohio back in late July and the brakes were much quieter afterwards. About a week and a half after getting back the brake squeal started to return. I am now in full dump truck/school bus mode....:mad I followed the recommended break in procedures for the pads after I initially got them. I may try to go back out and bed them in again, but at this point I will likely switch the fronts back to HPS. I could keep the HP+ and put them on before I hit any more road courses.Weird. They should be broken in by now. I don't think the HP+s are that aggressive and I havn't really had those problems before. Not sure what to tell ya.

[FromSVTtoM3]

So I went out and bed the brakes in again today. They are now noise free. The ASC/ABS lights haven't came back on since the first time. I do notice the occasional rolling squeal every once and a while though. Could it be wheel bearings? The car is has 80,000 miles on it and I have never replaced them since ownership(49K).

I agree with you Stuntman I don't think the HP+s are that aggressive either. I feel I would be better off just running HPS and then switching to a dedicated track pad before any roadcourses.

[das borgen]

OP

best advice for ABS/ASC lights is to go to a shop that has a BMW diagnostic GT1 tool (computer or standalone) and have them erase the codes, then go back to them when the lights come back on to see what part of your system has failed

It can be caused by
1) bad ASC actuator
2) bad ABS pump
3) bad ABS sensor
4) bad brake travel switch <----this was MY problem and is pretty common on the E36




Enthusiast Auto Group surely has one

[Schalldampfer1]

It could also be the Wheel Speed sensor being dirty or the Pedal travel sensor needing to be re-soldered.

[kornkid8600]

Ah that happened to me 5 years ago nearly.

The following were replaced:
Both front speed sensors were changed.
Brake pedal positioner and throttle positioner replaced
repair kit way sensor

But you know it can be a number of problems. If the ABS has a malfunction you'll get the ASC light also. They run on the same relay. That's why the trouble spots double and it could be one of many potential issues.

[kevinwilly]

It's pretty pointless to guess at these kinds of things. There are so many things it can be, and there are several fairly common problems that come up on these cars.

My light had been on for almost 4 years, ever since I bought the car. Dealer said it was a wheel sensor, but had forgotten which one. I didn't ever care enough to track the problem down.

I was at a friend's shop doing a smoke test to check for vacuum leaks a couple weeks ago, and I saw he had some nice scanner tool sitting there... I forget the name of it. Plugged into the X20 connector, though.

Plugged it in, said front right sensor fault. I changed it out a couple days later, and everything is working fine. Turns out it had a hairline crack in it towards the tip.

Previously, I had paid some place to check the codes and they told me aux throttle sensor, brake pedal travel sensor, left front wheel sensor, and all kinds of crap. I checked the pedal sensor and throttle sensor and they were fine. I think the shop was just trying to get me to spend money there. I didn't, for the record. Except for the scan, which was more about my airbag light. They said bad belt buckle, nothing they could do except replace it. I said I thought it was from me starting the car with the seat out one time.

Yeah, when I read the codes at my buddy's shop, I cleared the airbag light (passenger occ. sensor fault). Has not been back in 4 weeks.

Yeah- won't be going back to THAT place. Ugh.

Moral of the story- find a GOOD shop, get codes read, look at screen with your own eyes. I guess people that drive BMW's usually just throw money at their cars or something? Not me....

[das borgen]

Moral of the story- find a GOOD shop, get codes read, look at screen with your own eyes. I guess people that drive BMW's usually just throw money at their cars or something? Not me....


the shop that read my ABS code is great to work with and very fair (Best Motorwerks, in Columbus Ohio)


Like I said OP, check out Enthusiast Auto Group since you are in Cincy





oh, and join www.ohiobimmers.com (http://www.ohiobimmers.com) for more local help

[FromSVTtoM3]

Enthusiast Auto is where I bought my car from and where I have gotten all my work done from day one. I'm actually on Ohiobimmers under a different user name(bruceleejkd), but I don't post on there very often. I plan on taking the car by to them this week. I just wanted to get some people's input first since they weren't open over the weekend when this occurred.

[kevinwilly]

Enthusiast Auto is where I bought my car from and where I have gotten all my work done from day one. I'm actually on Ohiobimmers under a different user name(bruceleejkd), but I don't post on there very often. I plan on taking the car by to them this week. I just wanted to get some people's input first since they weren't open over the weekend when this occurred.


Ah, cool! I know those guys. They are great to work with. My college roommate lives in Cincy, and while visiting him I checked out a motorcycle vendor that is right down the road from Enthusiast... and while driving by I saw all the nice M cars and stopped by. I've been there at least 6 or 7 times to look over what they have.

mmm.... neat cars. :)

[FromSVTtoM3]

Yea they always have a few rarities on the lot. Both owners have track cars which they take out frequently

[Stuntman]

Brake Pedal Position Sensor (brake travel switch)

Part Number - 34 33 1 182 594

[das borgen]

Brake Pedal Position Sensor (brake travel switch)

Part Number - 34 33 1 182 594
great reason to revive this thread 3 months later, I guess

[Stuntman]

great reason to revive this thread 3 months later, I guessI'm still having the ABS problem as i'm sure many others are. I found the P/N for the sensor and will be trying that soon.

[Jim Bassett]

great reason to revive this thread 3 months later, I guess
Even better, the solution's been around for *7* years:
http://www.bmw-m.net/Digest/Archive_2003_12_digest_3492-3531/digest3531.htm#10

And posted here a few times since 2005.

:stickoutt :D