How To Guide The Dreaded ABS + Traction Control Light.

[sinahpr]

Hey everyone!
** Fair Warning: This is gonna take a ridiculously long time to reach any meaningful conclusion, but I'll do my best to speed things up **
With that out of the way let's get started.

The purpose of this post is to basically gather as much info as possible and compile a massive database (or hopefully a step by step diagnosis guid) for any Z3 owner with ASC/ABS issues.

Admittedly I am not a professional car mechanic, so if you're a professional, your input is most welcome and desperately needed at this point. If you've managed to solve your ASC/ABS issue please post your story/link to your thread/video and I'll add your story to the list. With the hope that future Z3 owners will have less googling to do when they inevitably encounter this horrendous nuisance.

My Particular Case:

The Story:
**TLDR at the End**
So my problem started 2 years ago. While casually driving down the road, I was met with the ungodly sight of the two yellow lights of doom on my cluster. I immediately proceeded to freak the hell out and try to pull over, before I even found a safe spot to stop, the lights turned off. It was as if nothing had happened. All systems functioned as they should and I just kind of shrugged it off as a random glitch.
6 Months later it turned back on and this time it lasted a good 5-10 mins, and went away after restarting the car. Everything went right back to normal.
5/6 months later it started again, but 10 mins became 30mins, became an hour, became a full day and finally, it remained permanently on.
I took the car to a shop with a code reader. the technician reset the onboard computer, the warning lights turned off and he said there's nothing wrong. He even ran an ABS pump test everything was absolutely fine. Sure enough the lights were right back on the next morning.

About 2 weeks ago I purchased an OBD-II reader with a pac-man port so I can finally find out whats wrong for myself. This bold and unprecedented move had my ASC module scared, understandably it didn't wanna go to the junkyard. So it started working again, as if it hadn't just spent the past several months being a useless hunk of metal.

So I took advantage of this and found a patch of slippery dirt to try and physically test the system, thinking I might get it to act up or do something weird. But nope. Nothing. Works like brand new.

Yesterday, it started raining quite heavily (not sure if related). This caused the unfortunate yellow duo to appear on my cluster again. so this time I wanna find out what's wrong once and for all.

TLDR: Traction Control + ABS Warning have been on/off intermittently for 2 years and Im tired of their s***.

The Car:
I have a Japanese market Right hand Drive 1999 BMW Z3.
its got the 1.9 litre i4 mated to a 4 speed slush box
Pretty much bone stock, except the rims and tires. Rims and tired were swapped out long before this issue arose. So it's unlikely to be causing it.
Progress/intro thread with more details:
https://zroadster.org/threads/japanese-market-z3-owner-new-to-the-forum.27995/#post-463282

The tests:
ABS Pump test (using onboard diagnosis) -pump fully functional
Visual Inspection of ABS sensors -they look fine
Pulled the fuse/swapped out for known good fuse -no avail
When the error is off:
-I tried to pull a massive powerslide -ASC intervened normally
-tried to do a burn out -ASC stopped wheel spin
-slammed the brakes as hard as possible -ABS stopped wheels locking up, not even tire squeal
When the error is displayed:
-ASC/ABS are completely shut off.

The tools:
Access to a crappy USB OBD-II reader from ebay
Access to Microsoft, Macintoch and Linux-based computers for running diagnostic software
Access to open testing area where I can slide around and do silly test manoeuvres safely
Actual Tools e.g. wenches, screw drivers, etc

Most likely Culprit:
Wiring Issue

The Task at hand:
Most importantly I'd like to know what software/hardware i need to properly access the ASC/ABS module.
The software that came with my OBD-II dongle can only show me engine data. If I'm not mistaken this car has a separate computer for the ASC/ABS system, is that correct?
What software have you guys used successfully?
Has anyone been able to access the ASC/ABS module with a run of the mill OBD-II reader?

Always Keep the top Down!
Sina

 

[Paul Rice]

Had similar problem with my Z3. Faulty N/S wheel sensor the problem.

 

[sinahpr]

Had similar problem with my Z3. Faulty N/S wheel sensor the problem.

thanks for the response! if you don't mind me asking, how did your issue present itself and how did you find out whats causing it? I wanna create a step by step guide so any bit of info is vastly appreciated.

 

[Robert N]

I've recently bought a good 2001 3.0 for a song because the ABS & ASC lights were on permanently and had been randomly coming on and off for some time. After much googling and forum searching I removed the ABS Controller module (4 screws and a wiring connector) took it down to my local HiFi repair shop with pictures of the most common fault (dry joints) where he opened up the unit, resoldered the joints and plastic welded the piece of cover back on - all done in less than 30 minutes and it cost me NZ$60. Everything is now fine.

This is a good place to start:
https://www.bimmerforums.com/forum/showthread.php?1102605-ABS-ASC-Lights-On-DIY-sort-of

 

[Jack Ratt]

I've recently bought a good 2001 3.0 for a song because the ABS & ASC lights were on permanently and had been randomly coming on and off for some time. After much googling and forum searching I removed the ABS Controller module (4 screws and a wiring connector) took it down to my local HiFi repair shop with pictures of the most common fault (dry joints) where he opened up the unit, resoldered the joints and plastic welded the piece of cover back on - all done in less than 30 minutes and it cost me NZ$60. Everything is now fine.

This is a good place to start:
https://www.bimmerforums.com/forum/showthread.php?1102605-ABS-ASC-Lights-On-DIY-sort-of

Great result Robert

 

[Paul Rice]

@sinahpr When i bought the car it was advertised with the intermittent fault, which very soon after purchasing, on the way home it became permanent ABS light on and stayed on. Plugged car into diagnostic which highlighted N/S/F speed sensor. Not that easy to replace as after years of been bombarded with road rubbish gets well stuck. Needed to drill out to replace.

 

[Stevo7682]

If the lights have come on there should be a fault code logged in the memory as to what put it on most likely to be one of the wheel speed sensors.

 

[roadvoyager1]

Symptoms in OP post are typical of dry solder joint problem that was documented on here a couple of years ago. My 1999 Z3 2.8 showed almost identical symptoms and threw up code 096 on the OBD.
Options to fix it are:
1. Cut top off control module and resolder.
2. Replace module with known good unit and recode to car.
3. Have unit refurbished at ecu repair company.
4. ......and yyou cannot be serious..... buy a new control module and pump from BMW at £1500++ then pay a shed load more to have it fitted.
Wheels sensors also create similar fault symptoms and are easier to replace so many people start with them and find the problem dis-appears.

 

[NZ00Z3]

Hi

Attached are my notes from various forums for the repair or replacement on the ABS module. I used them to replace the ABS module and code it to the car.

 

[Andyboy]

There are various ABS fixes on these. It all depends of which ABS block is fitted, as the Z3 spans both E36 and E46 models with later ones from late 1998 using more and more E46 stuff.

1.9's used to have problems with the combined ABS pump and ECU under the bonnet, the 896/897 ASC unit. The ABS pump was 896, the plastic ECU 897. They're shared with various E36 four cylinder cars and some earlier E46 316i/318i. You'll pay 50 quid for one, they're everywhere. Other 1.9's use the 1164 095 unit that was more reliable but is Z3 only.

2.8's can use either the old E36 323i/328i type with a separate ECU (1164 094) that can suffer water ingress or on later ones, the 896/897 ASC unit for cars with the Torsen LSD.

DSC cars have another unit again, with two hydro/electric pressure sensors on the master cylinder and a steering angle sensor in the steering wheel slip ring. These are all regular E46 bits and worth peanuts.

The last ABS problem I had was a car whose ABS light came on and off at random. The ABS would kick in randomly, normally on tight turns at low speeds. It showed a fault with the drivers front sensor - this was changed but to no avail. I then swapped the ABS block (and 896/897) for a known good one - still playing up. I then took a closer took at the sensor connector in the car loom and found it was green and corroded. I cut a plug from a scrap loom, cut and soldered it into the car loom and it was cured.

Changing ABS sensors is great fun. What I always do on a typical car where the suspension is old and rusty is remove the caliper and disc (15 mins) and then remove the hub/wheelbearing (sodding great nut) followed by the brake cooling backplate. Then you can hacksaw the end off the old sensor and beat it out with a hammer and big ugly screwdriver or an old 3/8 socket extension. They rarely come out without a fight after 20 years. Then you can go to work with a rotary file and really clean up the hole in the hub where it fits, and the new sensor slides in with a bit of grease to stop it rusting in again. You can do this with the disc etc on but unless the hole isn't completely clean there's a good chance the sensor won't sit in correctly giving a wrong air gap.

I've never bought a genuine ABS sensor, only 10 quid Ebay ones and they always work perfectly.

ASC units don't need coding to the car btw (they code themselves) but DSC ones do.