2002 E39 ASC BRAKE ABS lights on => Diagnostic Procedure & Parts Location

Oh my. My 2002 BMW E39 has these three lights lit on my instrument cluster:
- Triangle (is it ASC or DSC?)
- Brake
- ABS

I see there are lots of threads on this so I'm reading through them, but, they all seem to know already if it's ASC or DSC they're dealing with.

Am I dealing with ASC or DSC?

ASC (automatic stability control) apparently senses 4-wheel differential speeds during cornering and cuts the engine power via a second throttle butterfly valve to help keep you from oversteering and spinning out in wet/snowy/unfavorable conditions. It may also apply the rear brakes lightly in some situations. It apparently doesn't touch the suspension at all. It has been described as ABS in reverse. Reputedly, while ABS controls the braking force at all four wheels, ASC + T controls the power delivery of the engine, and the way the rear differential distributes torque between the two back wheels only.

DSC (dynamic stability control) in contrast, is apparently a suspension-control system which goes beyond Automatic Stability Control + Traction by monitoring steering wheel movement, vehicle speed, transverse acceleration and yaw to register imminent instability when cornering. DSC then intervenes via the engine management system reducing drive torque and activating wheel brakes when necessary to keep the vehicle stable.

Having said all that, how do I know if my 2002 E39 has ASC or DSC?
(I think it's ASC but I need to know before beginning my troubleshooting.)

Your 525 is 2002 which has the DSC. If I recall correctly the ASC is on the 1997, 1998 E39 US models.

Originally Posted by NFS

Your 525 is 2002 which has the DSC.

Thanks.

It's weird, but, for the past three days, sometimes the three triangle/ABS/Brake warning indicators are on, other times only the two ABS/Brake indicators are on, and other times none are on (see photos below).

I wonder if this problem is related to the fact I've been constantly disconnecting my battery to reset the DICE iPod interface.

Have you tried the warning light reset procedure?

Normally when you've got all those lights lit up, it's a problem with the DSC module.

When my ABS module failed those 3 lights would come on and then off when I shut down the car. The lights would come back on again after a little driving. I always got 3 lights thou.

Originally Posted by NFS

When my ABS module failed those 3 lights would come on and then off when I shut down the car. The lights would come back on again after a little driving. I always got 3 lights thou.

Same here. They'd go off sometimes, and then back on again a while later, but I'm pretty sure it was always all 3 lights. Of course, on my car I had the extra bonus that whenever I'd turn on the headlights, or the stereo up really loud, I'd get the transmission going into failsafe mode. I basically couldn't drive the car at night. That was related to the ABS module, as well (not enough eletrical current at the transmission control module).

If it is your ABS module, I'd recommend Module Master. They're also on Ebay under Circuit Solutions. They fixed mine and I think it cost me $325 including return shipping. They also provide a 5 year warranty on the repair.

Originally Posted by Elvis530i

Have you tried the warning light reset procedure?

I'm still in the "research" stage... trying to find the canonical DSC/ABS CEL brake troubleshooting thread.

In summary, after reading some of the many threads...

Is this the DSC/ABS/Brake warning indicator diagnostic procedure?
- Determine what is being displayed to me (I'm in this stage)
- Understand how the system works (sensors tied to modules tied to lamps)
- Locate the sensors (4?) and associated control modules (2?)
- Read the ABS CEL OBDII error codes with the Carsoft 6.5.1 hardware
- Reset the ASC/ABS/Brake warning indicators & test the car
... If the problem re-occurs ...
- Determine if the problem is in the sensors, and if so, which one(s)
- Determine if the problem is in the modules, and, if so which one(s)
- If modules, decide whether to fix the module & reprogram or buy new
- Install new (or fixed) sensors or modules & test the system again

Is that the basic diagnostic procedure for DSC/ASC/ABS CEL warnings?

You may want to consider BBA Remanufacturing. They could not fix my unit, but they will honor the warranty and they have great customer service. My indy now is saying that the problem is the "precharge unit," whatever that is. I'm undecided about fixing it--he quoted me $850. My ABS works fine and only my DSC light remains lit.

Originally Posted by bluebee

I'm still in the "research" stage... trying to find the canonical DSC/ABS CEL brake troubleshooting thread.

In summary, after reading some of the many threads...

Is this the DSC/ABS/Brake warning indicator diagnostic procedure?
Skip this step- Determine what is being displayed to me (I'm in this stage)
- Understand how the system works (sensors tied to modules tied to lamps)
Move this down to after you've read the codes- Locate the sensors (4?) and associated control modules (2?)
- Read the ABS CEL OBDII error codes with the Carsoft 6.5.1 hardware
- Determine if the problem is in the sensors, and if so, which one(s); replace the sensors
- Reset the ASC/ABS/Brake warning indicators & test the car

... If the problem re-occurs ...
- If modules, decide whether to fix the module & reprogram or buy new
- Install new (or fixed) sensors or modules & test the system again

Is that the basic diagnostic procedure for DSC/ASC/ABS warnings?

Fixed
Short answer is that either you've got an intermittent issue one or more parts, or you need a new module. Probably both….

Even after a full-fledged DICE battery reset procedure, I still have the DSC ABS BRAKE lights going on after a while of driving.

So, I'm gonna Carsoft the thing this weekend and let you know the codes so you can help me better.

One problem (a good one, I guess) is there is a lot of information about this problem scattered about - but I haven't found the one jewel of a thread (maybe we can make this one that so others benefit from our efforts).

Donna

Short answer: your module's shot and/or you need new sensor(s).

Based on the fact that it's intermittent and you've been fooling with the battery (I'm assuming the DICE install doesn't require you to get into you wheel wells or the steering column), it's the module. If you want to be sure, get the BMW STEALER (i.e. the guy with the expensive computer) to read the codes. Few aftermarket readers can.

What's the display going on about? Detached? Is that the DICE? Also, bloody cold in NorCal apparently!

Edit: It's possible to fix the module yourself, in some cases, apparently. Volvo owners have been doing it for a while. If you're handy with a soldering iron and have a vise and Dremel or hacksaw, you could try fixing it yourself. However, this assumes that you have chip creep with fully functional chips, rather than blown chips and solder in good shape.

Originally Posted by bmw_n00b13

Short answer: your module's shot and/or you need new sensor(s).

I know. I know. I hope to figure out the diagnosis procedure and document it in this thread (if it's not fully documented elsewhere).

My first task is to find a picture of the module and sensors (I think the sensor picture will be easy ... I might even already have one from my brake job - but where is the ABS module location in the engine bay?

get the BMW STEALER (i.e. the guy with the expensive computer) to read the codes. Few aftermarket readers can.

Do you think Carsoft 6.5.1 can read these codes correctly?

Detached? Is that the DICE?

Yes. Detached means the iPod isn't hooked up to the DICE at that moment I snapped the photograph. Otherwise the song name and artist would be displayed on the instrument cluster.

bloody cold in NorCal apparently!

Yea. It was "freezing" here in San Jose this morning. 60 degrees F at 6am at 60 miles per hour when I snapped that shot of my display. Brrrrrrr....

you could try fixing it yourself.

It may come to that. I don't mind purchasing whatever tools I need; it's what I do to get to the bottom of things.

What is the mysterious BMW OEM "repair kit" for the ASC control unit?

After a week now, I can report that I don't have the symptoms of intermittent speedometer but I do have all three DSC or ASC, ABS, & BRAKE lights lit on my instrument cluster after a period of time after I start the 2002 E39, so it's looking like either the 4 wheel-speed sensors or the ABS module itself.

If it's the ABS module itself, it looks like REALOEM lists it as:
E39 525i ASC hydro unit/control unit/support
01 Hydro unit ASC 34516756341 $2,003.22
02 Repair kit, control unit ASC 34526756343

Do you know what this BMW OEM "repair kit" is? It's not mentioned in the ABS fix DIY which says it can be repaired by these two companies:
1. Module Masters
2. BBA Remanufacturing

So, I ask, what is this BMW OEM repair kit anyway?

Also, do we have self-repair instructions handy (the bimmerfest search button is broken - it constantly reports "connection to three.performanceix.com:3312 failed".

Since nobody on Bimmerfest knew the answer, I called the local dealership who said that nobody ever buys the #1 thing called "Hydro unit, ASC"; he said everyone buys the #2 thing called "repair kit, control unit asc".

Prices out the door at the California dealership for parts are:
- #1 Hydro unit, ASC ===> $2,775 + $277 (~10% tax) = $3,052
- #2 Repair kit, control unit ASC ===> $1,120 + $112 (~10% tax) = $1,232
- 2x sensors front ===> $134 x 2 = $268 + $27 (~10% tax) = $295
- 2x sensors rear ===> $201 x 2 = = $402 + $40 (~10% tax) = $442

Is this the sum total of "suspect" parts?

Or is there an "ABS CONTROL UNIT" that we also need to look at?

- #1 Hydro unit, ASC ===> $2,775 + $277 (~10% tax) = $3,052
- #2 Repair kit, control unit ASC ===> $1,120 + $112 (~10% tax) = $1,232
- 2x sensors front ===> $134 x 2 = $268 + $27 (~10% tax) = $295
- 2x sensors rear ===> $201 x 2 = = $402 + $40 (~10% tax) = $442

Does anyone have a set of PICTURES of each of these parts in an E39?

Bluebee, were you able to determine how to read the wheel sensors? Seems like this is the hot seasonal item for some of us, your research is proving invaluable... I work with some aerospace engineers that don't have this type of analytical fortitude

Hi Bluebee! I'm having the same issue on my 540it at 84k miles. I totally missed that you were having this issue.

http://www.bimmerfest.com/forums/sho...3554&highlight=


Carsoft pointed out the right rear wheel sensor was bad. I reset the code, drove around a bit and it returned. So I first cleaned the wheel sensor:

• Take off rear wheel
• 3mm allen(?) to remove sensor retention screw
• Pull sensor out of hub assembly, straight up. A little twisting back and forth helps
• Clean with CRC electronic cleaner
• Replace sensor back into hub assembly, snug tighten
• Replace rear wheel, tighten to 88lbs.

Woo Woo! All lights went off.


Next day, all lights return. Replaced wheel sensor, but to no avail. I've been suspecting the ABS module as the light will go out when the car has cooled down, only to return when the car is heated up again.

Spoke with Jared at EAC. He confirmed the type of failure and symptoms. Noted that the false Carsoft reading could happen if the ABS Module itself was bad and not able to report status correctly.

I ordered a replacement new ABS/DSC Bosch unit from EAC for $450. I wanted the swiftest fix, with the least hassle. (I'll offer mine up for sale as a repair core if someone is interested, PM me next week) Once I install it, I'll head over to an Indy who can code the VIN into it and activate the unit with their software tools. For installation, 4 Torx bolts and an electrical connector I'm told is the extent of the physical installation. I'll take pics and post a DIY as a few folks have similar questions.

I could have used the DSC today as it is raining pretty steady, but instead, will drive nice and calm today...

Good luck Donna with your troubleshooting! I know it will result in good info for us all as usual!

Originally Posted by bluebee

Does anyone have a set of PICTURES of each of these parts in an E39?

I might, tomorrow, if my mom lets me steal her camera and pull my wheels off. I believe QSilver7 may have some of the pics. The first attachment is the DSC connector in the car. The silver part is the hydro unit; the black part (also featured in the second image) is the module, which I believe to be the repair kit.

- #1 Hydro unit, ASC ===> $2,775 + $277 (~10% tax) = $3,052
That seems to be the hedgehog-like bit that the ASC control unit bolts on to; i.e. the milled aluminium part.
- #2 Repair kit, control unit ASC ===> $1,120 + $112 (~10% tax) = $1,232
Plastic bit that everyone sends in. The "module". As far as I can tell. Very expensive apparently; shouldn't be that much. If it comes to it, email Jared.
- 2x sensors front ===> $134 x 2 = $268 + $27 (~10% tax) = $295
- 2x sensors rear ===> $201 x 2 = = $402 + $40 (~10% tax) = $442
You saw them when you did the brakes. BMW will probably charge an hr labour. A child could do it once the wheel is off. It's technical like an oil change

You have DSC. Not ASC. Don't mix them up! The ASC module is much more expensive than the DSC afaik. There's several major differences as well. The dealer should've pointed this out if you called about an '02.

Originally Posted by BlackBMWs

For installation, 4 Torx bolts and an electrical connector I'm told is the extent of the physical installation. I'll take pics and post a DIY as a few folks have similar questions.

Woo hoo! That's what I was hoping to find. I've been very busy lately (relationship and work issues galore) so I haven't even checked the Carsoft yet.

It's interesting that it didn't really help you (apparently because the ABS gave bad input about the probably-good sensor) - I'll report what my results are ... hopefully this weekend as I mope around all depressed!

Originally Posted by bmw_n00b13

You saw them when you did the brakes. BMW will probably charge an hr labour. A child could do it once the wheel is off. It's technical like an oil change .

Your talking about the speed sensors? Those are not always easy to get out. Esp the back ones as ive had to remove the parking brake assembly a few times to get them out. Should take an hour, but on occasion it is a much harder job.

Originally Posted by dannyc9997

Your talking about the speed sensors? Those are not always easy to get out. Esp the back ones as ive had to remove the parking brake assembly a few times to get them out. Should take an hour, but on occasion it is a much harder job.

I'm trying to find a picture of the ABS speed sensors in my brake thread but I can't find any pictures that look like the sensor.

I can find the sensor CONNECTOR but I don't know which picture shows the sensors.

Im going to be doing my rear drivers sensor (hopefully) tomorow. I will upload some pics to this thread then.

Originally Posted by bluebee

I'm trying to find a picture of the ABS speed sensors in my brake thread but I can't find any pictures that look like the sensor.

I can find the sensor CONNECTOR but I don't know which picture shows the sensors.

Just follow the wire to the sensor.

Originally Posted by bluebee

I'm trying to find a picture of the ABS speed sensors in my brake thread but I can't find any pictures that look like the sensor.

I can find the sensor CONNECTOR but I don't know which picture shows the sensors.

Here you go...

Sensor in the rear Passenger wheel hub.



Business end of the rear Passenger wheel sensor.


Where it's positioned in the wheel hub


Both ends of the ABS wheel sensor.

Originally Posted by dannyc9997

Your talking about the speed sensors? Those are not always easy to get out. Esp the back ones as ive had to remove the parking brake assembly a few times to get them out. Should take an hour, but on occasion it is a much harder job.

I wonder if the Sedan's wheel hub is different that the Touring's. Access to the Touring wheel sensor is pretty easy once you get the road wheel off. Two minutes to unscrew it, three if you have to twist it back and forth.