ABS and ASC light stay on

Hello all

Wondering if anyone out there might be able to help with a problem relating to a 1997 528i AUTO.

I have noticed in the past few weeks that the ABS and ASC lights stay on after starting the car, pressing the ASC switch does not switch the light off and the ABS light stays on. This has been happening at least once a week. and usually after the car has been driven (appox. 15miles) and then parked for a period of time(anywhere from 2 hrs to 8hrs).

I have switched the car off and "pumped" the brake pedal a few times and then started the car (I do this a couple of times) and the ABS & ASC lights switch off along with all the other warning lights on the dash. This is really annoying, has anyone out there experienced the same problem and does anyone know what the problem might be and how to fix it.

Thanks in advance to all that can offer some advice.

My car's quite a bit older than yours, but it might be the same problem. The ABS light can come on if your hubs are rusty or dirty. The hubs have ridges on them, and the ABS sensors sense these ridges to know if the hub is turning or not. When the hubs get rusty or dirty, the sensors can't pick up a signal, and they freak out.
Go to the car wash and do some serious washing on each of your hubs. Lean over and blast some water from underneath the car onto the hubs as well. It's a cheap start, and if you still have to have some work done, the mechanic will thank you.
Flunky
PS-My ABS light went off after I did this. That was a year ago.

Thanks for the advice I'll give it a try.
Am I correct to think that I should clean all four (front & back wheels)?
Also, when you say "hubs" what exactly are you referring to?

Hi. If you take off a wheel, the part that the wheel bolts to (the part that spins) is the hub. It'll have some ridges on the outside edge.
Yes, you should clean all four.
Good luck.
Flunky

Thanks for the clarification...Will try power washing the "hubs" like you have suggested.

I am a little confused though, the ABS light and ASC light do not come on while the car is in motion only after it has been parked, engine turned off and subsequently started. If they come on and remain on after the car has been started (still parked) I assume the hubs are stationary so the sensors should sense that the ridges on the "hubs" are not turning, do you still think the problem is related to "dirty/rusty" hubs?

Also, where are the sensors located? How many are there?

Thanks in advance for your help.

What a beautiful day it was yeserday. THe sum shining and not a cloud the sky. Like numerous others I washed&waxed the car and as you suggested I spent a little extra time "power washing" the hubs. I ABS and ASC lamps on the dash come on and turn off after the car has been started as they should. I hope that was the problem and it's been fixed, only time will tell. I'll keep you posted.

Unforntnately, this common problem as nothing to do 'dirt' or comnamination of the wheel hub trigger wheels, BMW's unlike MBZ were never susceptible to this. The most common failure though they will be quite intermittant at first is the ASC Control Unit which screws to the Hydraulic Unit mounted on the R/F wheel house and is easily replaced. Fault Codes may include wheel sensor failures but actual testing [which is part of true diagnosis, not dart throwing} will show perfect output patterns] and when they test good [which they always have in my experience] replacement or 'cleaning' is a waste of time.

Hope this helps...........................jeff b.

It just happened again, started the car this morning and everything was fine. Parked the car for approx. 6hrs and then when I returned and started the car the ABS and ASC lights came on and stayed on, I turned the car off and pumped the brake pedal 3-4 times and started the car again but the lights remained on (tried this 3 times). I then drove the car home appox. 15 miles with the ABS and ASC lights on.

Any suggestions on what I might try at this point or do I need to get it into a shop ASAP because things may get worse quickly or it is a danger to drive it with those lights on.

Thanks again to all those that can offer some advice.

Did you read my post? It's just above your last one. If it wasn't clear enough, YOUR SYMPTOMS POINT TO A VERY COMMON CONTROL UNIT FAILURE.........it needs to be replaced..................jeff b.

I ain't no expert BUT if you drive with the ABS light on it kinda implies that the ABS isn't working. UK Insurance companies are now taking a very dim views of this and if they can prove that in the event of an accident that the ABS wasn't functional, thay might be inclined not to pay out. Not to mention potential police prosecution. Just a thought.

Anyhow, I have had both ABS+ASC lights on constantly, beginning last week. Took car (520 E39 1997) to dealer yesterday and, contrary to meddling with the sensors, they've replaced my disks and pads, plus a wheel bearing. Warning light problem now fixed. No sensor cleaning or replacement. I'm collecting my car today and have asked for the old parts back, (seeing as they're mine!)

2 hours labour! :mad:

Might be worth giving the dealer a chance. They'll suss it out and let you know what it needs before actually fixing it.

Good luck.

For a couple of months, my ABS light was on. Just for the entertainment of myself and my passengers, I stomped and held the brake down for a long, long time while going about 70 mph. The front wheels locked up. I let off for a moment, then stomped and held it again. The front wheels locked up once again.
Yup, when your ABS light is on, you can't count on the ABS to work!
Thanks for trying my suggestion, even if it didn't solve your problem. Read Jeffrey's post. He has very detailed information based on experience.
Flunky

Thought I would let you know that the lights went out as they should after I drove home yesterday, parked the car and went out a couple of hrs later. The ABS & ASC lights have not remained on since yesterday evening.

I will have the problem looked at the next time it happens and let you what is the cause...it would not surprise me if the ASC CONTROL UNIT needs to be replaced as Jeff B has suggested.

If it is the ASC CONTROL UNIT...does anyone know what it might cost to replace (parts&labour)?

Thought I would let you know that the lights went out as they should after I drove home yesterday, parked the car and went out a couple of hrs later. The ABS & ASC lights have not remained on since yesterday evening.

I will have the problem looked at the next time it happens and let you what is the cause...it would not surprise me if the ASC CONTROL UNIT needs to be replaced as Jeff B has suggested.

If it is the ASC CONTROL UNIT...does anyone know what it might cost to replace (parts&labour)?

Dude usually when ABS light comes on that means that you need rear brake pads u might wanna check that before throwing money away!

My E34 ABS light was on also, but it occured when i was driving at some 80mph
after wheel balancing, putting weight, it went ok

when u drive at does the steering wheel shake?

Did you read my post? It's just above your last one. If it wasn't clear enough, YOUR SYMPTOMS POINT TO A VERY COMMON CONTROL UNIT FAILURE.........it needs to be replaced..................jeff b.

I believe you're right about replacing the sensor. I]ll know more this week when I drop my car(2000 528i) off at my BMW dealer for troubleshooting. I should add that my speedometer stopped working when the ASC and ABS lights came on, and the cruise control fails as well. Seems they're all linked together. I'll let you know the outcome later this week. FN

I believe you're right about replacing the sensor. I]ll know more this week when I drop my car(2000 528i) off at my BMW dealer for troubleshooting. I should add that my speedometer stopped working when the ASC and ABS lights came on, and the cruise control fails as well. Seems they're all linked together. I'll let you know the outcome later this week. FN

Hi Fred-

What was the outcome? I'm having this same problem with my 2000 528i.

My ABS and ASC lights only come on and stay on at certain times.. I have also changed my front brake pads yesterday and the warning light is still on... I need to replace the brake sensor... Does this brake sensor work with the ABS sensor as well or would that be a different circuit? (There's only appears to be one wire attached to the brake calliper... (passenger side)
So when I change the brake sensor it may make all 3 warning lights go out...?