ABS Control Module - Repair / Replacement Cost


Roadandguitarman
06-10-2006, 11:57 AM
How much should it cost to repair or replace the ABS Control Module on a '98 VW Passat?

jsmr
01-06-2007, 09:15 PM
Did you ever have any luck in replacing the ABS? Someone has suggested that I just have it unplugged. We know that the module isn't getting communication, but the guy thinks that it could be a loose wire in the wiring. How did yours turn out?

Roadandguitarman
01-06-2007, 11:22 PM
I still haven't gotten my ABS fixed, yet. I'm still trying to decide what to do. It's going to cost almost $1K to replace only the ABS electronic control module. That part is called a "kit" because it doesn't include the hydraulic unit of the ABS. To replace both together (hydraulic and electronic) would cost about $1.5K at the dealer.

Instead of paying so much to have the ABS fixed, I just put a small piece of black electrical tape over both the ABS and Brake lights on the instrument panel. The 3 beeps still occur each time we drive it, but we have gotten used to that.

I just hope that a bad ABS doesn't affect the normal braking system in any way. I did read somewhere that it does reduce the braking power of the rear wheels, but I don't know how much and whether that is true or not.

Does anyone have any information or advice on what else I should do? And, by the way, if I just unplug the control module, will the car pass the annual Virginia State Inpection?

Bones3
08-03-2007, 08:39 PM
I had the same problem with my 01 Passat. BBA Remanufacturing has an excellent web site (BBA Reman .com?) detailing how to replace the ABS module. I purchased a remanufactured module and following their instructions, now have my ABS back. cost about $175. fairly easy do it yourself.

antiekeradio
12-08-2009, 09:25 AM
Hello,

The 'default' error mode of these (Bosch 5.3) ABS controllers is 'no communication with controller' usually intermittent.

The cause is a broken wirebond linking voltage supply to the processor print.
These are two parallel 0,3 mm aluminum wires that have been welded on the surface with ultrasonic.

DIY repair is possible if:

- you have a VERY steady hand
- you have VERY good eyes
(alternative: effective magnification equipment (reading loupe with circular light will do I guess)
- you have a clean, well-lit workspace with no distraction from pets, children, spouses, telephone etc.

Take out the controller as described on various websites that offer repair services. depends a bit on the vehicle how to do it, read up before starting.

With the controller on the table before you; use a long but thin knife and a hammer to open the cover. Place the knife on the bonded edge. Carefully tap the knife so that the bond comes loose, mil by mil. Or use some other method that avoids flakes getting inside.

You need Silver Epoxy (silverglue, silverpaint, conductive paint) to repair the connection and some chemically neutral glue or resin to stabilise the repaired spot.

Take off the clear coating on the wire as shown in the pictures. DO NOT APPLY ANY FORCE, HEAT OR CHEMICALS on it. SOLDERING WITH A NORMAL IRON WILL KILL THE CONTROLLER!!! the gold pads will come loose!

Do not touch the coating (gel) on other locations than indicated. The gel covers wires that run from processors to substrate (white board) which are almost impossible to see with the naked eye. kill one such wire and you can bin the unit. If some fragments of the cover are stuck to the gel you can/should take them off using a pair of tweezers. grab and lift at the same time, don't press them any deeper in the gel!!!

The trickiest bit is where you need to scratch the surface of the aluminum slightly to ensure good connection with the silver epoxy.
To ensure that the silver epoxy remains 'floating' between the wires you might need to bend them a wheeee bit so that they are closer together.

Dry the silver epoxy with some incandescent lamp nearby; this improves the conductivity. apply a thin layer, dry, then another layer.

Put on the cover with some tape and let it rest for a few hours.

test the controller on the vehicle. Don't forget the 2-wire connector at the bottom as this throws error codes that need to be reset with VAG-COM or dealer.
If the repaired joint is conductive the controller will be alive and communicating with the car. The ABS light should come up at contact and go off after two or three seconds.

When this works we can wrap things up; take it back inside and apply the stabilising glue. Now you can close up the module definately (use whatever works for you, as long as the seal becomes strong, heat resistant and watertight it will be just fine) and let your repair work dry for 24 hours.

Assembly, testdrive to make sure ABS works. If yes; feel like a hero :grinyes:

Disclaimer: When doubting your own capacity to do this repair, you're probably right. Prove me wrong at your own risk!!! :icon16:

When you are reading this your ABS module is probably shot already, so what have you got to loose? I think it is much much much better to give this repair a serious attempt then to stick a piece of tape on the warning light :nono:

In countries / states where ABS is part of the mandatory safety check, it usually is required to have the lamp turn ON at switching on the ignition.

PICTURES

Cover Off:

http://www.antiekeradio.nl/deeplinkimages/audi/abs/ABS1.jpg


Gel off, ready to repair. You can see that the shiny reflective line you see on the aluminum has a small interruption on the left, right in the middle of the bend. That's your circuit break!!

http://www.antiekeradio.nl/deeplinkimages/audi/abs/ABS2.jpg

Silver Epoxy to the resque:

http://www.antiekeradio.nl/deeplinkimages/audi/abs/ABS3.jpg
(note the wirebonds connecting the white substrate with the processing chips, the microscopic size of it all is just scary)


My method of sealing/closing the cover afterwards (can be reopened) using spring wire.

http://www.antiekeradio.nl/deeplinkimages/audi/abs/ABS4.jpg

Thanks to:

- user N3IDT (http://forums.qrz.com/member.php?u=252575) on http://forums.qrz.com/showthread.php?t=171525
- some russian guy running passat-b5.ru; http://passat-b5.ru/remont/abs/
- my dad for making the spring wires and helping with opening the cover, material supply etc.

Greetings from the Netherlands

Wouter

antiekeradio
12-08-2009, 09:34 AM
can someone look into the moderation queue for this thread?

I put a _huge_ post in it, but the background was white and it looked a bit more like a 'archive' page. after posting it said 'your message is placed in the moderation queue'

'97ventureowner
12-08-2009, 10:10 AM
can someone look into the moderation queue for this thread?

I put a _huge_ post in it, but the background was white and it looked a bit more like a 'archive' page. after posting it said 'your message is placed in the moderation queue'

Yes, when a member posts a post like you did, it is sometimes sent to a moderation queue for a Moderator to review and approve. It is done this way mainly to prevent spammers from posting advertisements . Certain things trigger the site software to tag a post like this such as a large number of pictures, or links. It isn't a problem and members shouldn't be discouraged from posting helpful posts like this. Just realize the approval process may take from a few minutes to several hours depending upon the availability of Moderators online to review posts in the queue.

antiekeradio
12-08-2009, 01:19 PM
Thanks for the explanation, and sorry for the panic :rolleyes:
(I thought something had gone wrong because my later posts referencing to this thread showed up immediately)

I happen to be admin of a vBulletin board myself, but that is not in English (it's Dutch, actually) which significantly lessens the spam pressure.
To keep out automated registrations I installed a simple 'silly question' system that ask very, very simple questions that anyone who can type the URL can answer, but impossible to guess by a computer. Users report this function as more userfriendly than CAPTCHA, and in 3 years it only let one or two bots by. (changed the questions once they started getting through, clean ever since)

Anyway its interesting to see a anti-spam system in action that judges the actual contents of the messages by certain criteria.


And I certainly hope my post was useful. I see it mainly as the alternative for either coping with or disabling the error light.
For me personally the cheapabs.com repair service turns out much more expensive because of the shipping costs, but if we had a similarly priced service over here I guess I would have paid to have it done.


Regarding safety, I can understand if people think its unwise to 'meddle' with security systems like ABS. However, I reviewed the design of the unit and it turns out it was built with a lot of "fail safe" situations in mind:

1; The two processor units on the print are fed the same input, and process it in the same way. The results are compared and only used if they match. (i.e. if you break one or two wirebonds on the print, the module throws an 'internal error' code and stops working)

2; All valves are controlled by separate processors, that can determine if the valves are working or not. break a wire to the solenoid and it throws an error and stops working)

Another thing to keep in mind is that the repair shops that offer this repair commercially are not qualified by the manufacturer to do it, but still they do and give years of guarantee on it as well, without asking you to sign disclaimers, etc... Even if the whole controller is melted together with the soldering iron all that happens is a fuse that blows and then you still have your normal brakes.

beanfisch
01-27-2010, 11:27 PM
antiekeradio
I want to thank you so much for your post about the module for ABS. I used your post to finish work on a Passat I was working on. It saved me a bundle. Your complete instructions were top notch and it worked perfectly. I had been trying to figure this ABS issue out for almost a week :banghead:. But could not get past the "linking error" on scan tool. I wanted to make sure you know that your help was something I wasn't able to find :1zhelp:until I came across your post. So THANK YOU!! THANK YOU!! :smile::thumbsup:
May you be forever blessed.
beanfisch

antiekeradio
02-01-2010, 06:32 AM
Hello beanfisch,

You're most welcome.
Thumbs up for the succesful repair! Very glad to see that my instructions have been of help.

Greetings, Wouter

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