Hand brake problem, or should I say button???

[neromonk]

I am also experiencing intermittent failures of the parking brake button in my 2007 B6 Passat wagon. The symptom is the brake will not activate and a 'Park Brake Failure' message comes up in my display. The yellow light in the button flashes and the red brake symbol in the dash also flashes if I hold the button down for any length of time. With some perseverance, it usually comes right again after an arbitrary number of attempts.

My VCDS shows:

Address 53: Parking Brake Labels: 3C0-907-801-53.clb
Part No SW: 3C0 907 801 G HW: 3C0 907 801 G
Component: EPB VD8HC005 013 0005
Revision: 013
Coding: 0000012
Shop #: WSC 131071 1023 2097151
VCID: 2665DA7391D9262ECEF-8073

2 Faults Found:
02443 - Control Head
008 - Implausible Signal - Intermittent
Freeze Frame:
Fault Status: 00111000
Fault Priority: 2
Fault Frequency: 3
Reset counter: 10
Mileage: 97368 km
Time Indication: 0
Date: 2013.12.31
Time: 14:06:42

Freeze Frame:
Voltage: 14.08 V
Count: 46

02443 - Control Head
012 - Electrical Fault in Circuit - Intermittent
Freeze Frame:
Fault Status: 00111100
Fault Priority: 2
Fault Frequency: 2
Reset counter: 10
Mileage: 97320 km
Time Indication: 0
Date: 2013.12.30
Time: 09:01:16

Freeze Frame:
Voltage: 11.59 V
Count: 40

I spoke to a local dealer today while I was there for another matter and they diagnosed a faulty button which they would replace for $280. Im not sure how much diagnosis they did or whether they were just going on past experience.

My question is how could it be a faulty button? My car's system knows that the button has been pressed because it flashes lights and displays messages in response to me pressing it. What doesn't happen is the brakes are not activated. If the button is a simple open/close contact, then the contacts are closing and opening when they should in response to me pressing it. What more could a button be expected to do? Yes, there is a light inside the button, but this is also working as it goes on steady when the system works and flashes when it doesn't. So the contacts and the lamp are working, what else could be faulty?

I have read in other forums that disconnecting the car battery for a while and reconnecting will also solve the problem, but sometimes only temporarily. It also seems that replacing the button is also sometimes a temporary solution and sometimes it needs to be replaced again later.

So what is the real problem?

I'd be interested to know how much the new module cost that RedDiablo had replaced. As I understand it is a highly complex unit and it takes a lot of disassembly to access it. I wouldn't want to replace that unless absolutely necessary.

Is it just a case of replacing something or disconnecting and reconnecting something can make the problem go away for a variable length of time? I'm tempted to disconnect and reconnect the switch (cleaning the contacts) and maybe disconnect and reconnect the battery and see what happens. But there must be a better way to solve this.

Any other thoughts?

[RedDiablo]

Hi Neromonk,

In my case the dealer put in a "Goodwill" claim to VW. I didn't request this so not sure whether it was due to the relatively low kms of the car. VW's response was apparently a 50/50 cost share for the repair. The total cost for the initial inspection & diagnosis before Christmas and the subsequent supply and installation of the new module in early January was $757.10.

If you google the part number it is available on a few OS web sites but not sure on the change out process or required resets via VCDS.

As mentioned in an earlier post I had already changed the switch myself prior to the above repair at a cost of around $95. I purchased the switch from a different dealer and the change out process was very simple with the help of Google although the release clip to unplug the switch from the wiring loom was a pain to operate.

After replacing the switch I tried the disconnect battery trick to to see if that would reset the error without success.

[Umai Naa!!]

The switch fixes 90% of EPB faults.

I would start with a new switch, and go from there. It's relatively cheap in the scheme of things, and easy enough to replace.

[Transporter]

The new switch may help in some, but most likely it needs the software update.

Sent from my GT-N8000

[neromonk]

Following on from my initial post, about 4 posts above this one, here's what's happened next.

When the problem reoccurred for me, with the parking brake not releasing in response to pressing the button, I tried out one theory that I had read that the brake could be released by driving off. I know this is what happens when the system is working properly, that is the parking brake releases when you press the accelerator to go. I've done that a few times myself and with a little jolt, the car takes off. But I found that trying this method when there is a fault doesn't work. When the brake wouldn't release in response to the button and the message 'Parking brake fault, refer manual' was displayed, I initially tried reversing out of my parking spot but couldn't go anywhere. I tried going forward but still no progress. I'm sure if I had persevered with this experiment then my clutch would have let go long before the brakes ever did! So I just resorted to my usual solution of turning the ignition off and on a few times and pushing the button at random intervals and eventually it came good and off I went.

I have checked that I have all the latest parts installed. My button has a date code of 3057 which is day 305 of year 2007 according to Technical Bulletin "46 08 04 July 31, 2008 2017924". This tech bulletin says that new switches from production date 2606 are the good ones.

My control unit and programming should also be good as Technical Bulletin "01 07 47 May 15, 2007 2015075 (Update Programming, Electromechanical Parking Brake (EPB), to Prevent False DTCs)" says that the new control module is Part No 3C0907801G and new software version is 0005 or higher.

My VCDS readout shows "Part No SW: 3C0 907 801 G HW: 3C0 907 801 G" and there is also a 0005 suffix on the component number and Revision 013 and Coding 0000012 which all are greater than or equal to 0005.

Now, going back in history I checked my old paperwork and reminded myself that the car had been towed to a dealer in April 2008 when it was just over a year old and the parking brake had played up. It was fixed under warranty and the paperwork description reads "Checked for handbrake fault in system and diagnosed control unit and programmed to vehicle. Now all OK. VW3C09070801G Control module". So that is probably when this car got the updates.

So what's gone wrong now? I don't know but I decided to follow the wisdom of this forum and when I was at a dealer for another matter today I purchased a new switch for $100 and came home and fitted it. This switch appears to be a slight update on the existing one. It has a "C" instead of a "B" at the end of the product code. This one is 3C0927225C REH and has a date code of 0703 which I assume is day 70 of 2013.

That little blue clip on the connector makes fitting very difficult but I used some long nose pliers to squeeze that one. With the new switch fitted, I thought I better go the whole hog and perform the terminal 30 reset of the EPB control module as described in Technical Bulletin "46 08 04 July 31, 2008 2017924". That is, disconnect the battery, wait at least 10 seconds and reconnect the battery and operate the parking brake twice with the ignition on and the brake pedal pressed.

Well, I did that (I'm very cautious and always get a fright when there are sparks from the battery terminal when I reconnect) but the parking brake would not operate. I tried ignition off and on a few times, foot on and foot off the brake pedal, in park and in neutral in various combinations but the parking brake stayed on and the MFD displayed "Depress brake pedal!" every time I pressed the button. Of course I was already doing that and the rest of the car's system recognised this fact as it let me move the gear selector from park to neutral when my foot was on the brake, for example.

I tried a second terminal 30 reset, more sparks from the battery, but the same (non-)result from the parking brake.

Then I started the engine, and to my immense relief the parking brake operated normally. Backed out of the garage and drove back in and all worked properly.

Let's see how long this fix will last. I'll let you know if it doesn't.

And finally I will correct my assumption in my previous post that the button is simply a set of contacts and a lamp. There are actually 8 wires connected to this unit, so there must be some semi-intelligent functions carried on inside the button itself. I suppose it has to communicate with the CAN data bus and from other references that I have seen it also connects to the ABS control unit. So maybe it is more sophisticated than I first thought.

[neromonk]

Me again… I will now retract my correction in my previous post.
Having decided that my faulty parking brake switch is not much use for anything, I decided to disassemble it to see what makes it work.

It really is just a couple of pairs of contacts and a lamp, in essence. Although, of course it has been designed to be a bit more than that. But there is no mysterious technology or software logic involved.

The 'switch' part is actually two separate surface-mounted pushbuttons on a small circuit board. They are wired separately to four of the pins on the connector, which goes part way to explaining why there are so many pins on the connector. They must do two separate functions or provide open/close signals to two different units, maybe to the park brake controller and the ABS controller, for example.

The other four pins on the connector are for the lamp. There is a ribbon cable going to a second small circuit board which has a transistor and three resistors on one side and three surface-mount LEDs on the other. So no magic there.

This then begs the question of what goes wrong with these hundred-dollar pushbutton parts. It could be one or other of the pushbuttons. Maybe one works and the other goes faulty which then confuses one or other of the controllers that they are connected to.

Or, my other theory is that it could be the connector pins themselves. These pins are just push-fitted into plated-through holes in the circuit board they are connected to. There is no additional solder on the joint. After a bit of vibration and a few years of oxidation, the connection between one or more of these pins and the holes they are pressed into could become somewhat intermittent. I reckon that for a hundred dollars they could have included eight small daubs of solder to prevent something like this happening.

So if my new switch goes faulty sometime down the track, I'll look back at this thread and remind myself to disassemble the back part of the switch and try to get small dots of solder onto where the pins push into the circuit board using a fine-tip soldering iron (if my eyesight is still in reasonable shape by then).

Hope this helps someone.

[Umai Naa!!]

I'm not aware of any version C switches failing, but of course, I'd never rule it out.

[slitko]

My button on my Passat was flashing and beeping. Took it to dealer service and they diagnosed the problem as the brake control module that controls the electronic brake, auto hold function and hill hold. The price is $1800!!

Is this price correct or am I being overcharged? I thought it would just be around $100-$300 to change the switch

[Umai Naa!!]

Yeah, EPB modules do fail sometimes.

Not sure how much the module is, but the job doea take some time to do.

[Deep Blue]

Had to bump this thread!

After a scan with Foxwell scanner and a detailed read through this forum and others I reckon I need to swap out the EPB switch (2009 Passat CC 2.0L TDI) as an obvious and cheap first step. Prices for EPB switch part#: 3C0927225C as follows:

Melbourne dealer - $117.70 pick-up from dealership; incidentally the dealer uses part#: VW-3C0927225CREH

Melbourne based eBay seller (and VW mechanic) - $27 delivered (described as "...quality aftermarket...")

Aliexpress.com - USD 2.99 (many sellers, but most charging less than USD 8.00 delivered - standard delivery though is 4 - 6 weeks); aliexpress seller uses two alternative part #s: 3C0927225C or 3C0927225B

Any thoughts or experiences to share?

Given the price, might just buy one from aliexpress (from buyer who has more sales)?

Any suggestions or things to watch out for?