!!!!Electronic Parking Brake Malfunction!!! Workshop!
 

It must be that time of the year again.

I replaced the left side connector and caliper with motor over a year ago and did a really good job of the wiring repair, I'm sure it is not that and have tested the pins of the plug that goes into the control module - At the control unit plug, the readings are the same on the left and right and as directly at the caliper plug, so think the wiring and motor are OK.

Attachment 17648 Attachment 17650

For around a month, I had intermittent parking brake error messages
and the left side has had "clamping for not reached" and "implausible pad wear" errors. See screenshot, group 3 is 13A left and over 15A right. 15.0A is the minimum permitted.

Attachment 17647

After lots of playing with VAGCOM, doing adaptations, pad wear recodes, fault code resets, disconnecting the battery, it got worse and sticks on almost every time I disengage it, and I have to turn car off for a few minutes and retry and then so far has been ok. The errors are permanent now.


The control module, and caliper connector were already replaced by Audi under warranty for the original owner in 2007 so the module is a year newer than the car. They made a mess of the connector which is why I had to do it again. As you can see below, the software version is 0230

Attachment 17649

I was wondering if other A8'ers can tell me their SW version from their VCDS scans and the model year of car.
Also, the label on the control module says 023 on it and I wondered if that was to do with factory SW version.

I saw one on ebay that had a 2013 manufacturing date! but the listing was pulled by the seller.

THANKS!


Address 53: Parking Brake Labels: 4E0-910-801.clb
Control Module Part Number: 4E0 910 801 D HW: 4E0 907 801 B
Component and/or Version: EPB A4EC0230 H03 0230
Software Coding: 0000221
Work Shop Code: WSC 00097 210 194805
VCID: 20446925F3957546B1-8075
3 Faults Found:

02432 - Supply Voltage for Left Parking Brake Motor (V282)
011 - Open Circuit - MIL ON
Freeze Frame:
Fault Status: 11111011
Fault Priority: 1
Fault Frequency: 8
Reset counter: 41
Mileage: 415760 km
Time Indication: 0
Date: 2017.12.18
Time: 08:56:39

Freeze Frame:
Voltage: 13.35 V
Count: 116

02596 - Rear Brake Pads Worn
008 - Implausible Signal
Freeze Frame:
Fault Status: 01111000
Fault Priority: 6
Fault Frequency: 2
Reset counter: 37
Time Indication: 0

Freeze Frame:
Voltage: 9.52 V
Count: 61

02428 - Left Parking Brake Motor (V282) Clamping Force Not Reached
000 - - - Intermittent
Freeze Frame:
Fault Status: 00110000
Fault Priority: 4
Fault Frequency: 4
Reset counter: 81
Time Indication: 0

Freeze Frame:
Voltage: 10.87 V
Count: 14

I'm not sure if this helps or not, but I had a couple of parking brake malfunctions recently in the cold weather - for about 3 days straight, however, I suspected that the cold weather and err, leaving my lights on all day meant that the battery was low.

Sure, enough, cleared the codes in VCDS, shoved the car on the CTEK overnight and voila, two weeks so far of driving with no parking brake malfunction errors and no codes logged.

Might be worth a try mate

Thanks mate - it does seem to be the cold damp weather, and it may have been low voltage that triggered it but I have had the charger on until 100% and left connected to no avail.

I have found that the connector under the battery for the controle module is the same on various models, A8 4H, A6 etc... and some VWs. So i looked at the pinouts in the current flow diagrams of my A8 and a post 2007 A6 and they are all the same apart from the hall sender pins are redundant (still there on control module end) but just two pin at the caliper end instead of our 4. I woud love to try one of these. On the 2007> A6, they updated the software to be more reliable, better voltage monitoring and algorithms - no longer has hall senders or counts revolutions and no longer has pad wear monitoring. All the pinouts for +, -, pressure switch, cluster lamps, CAN etc etc... are the same.

The Audi A8 4H 2010> is the same too. Hmmm. Could this be a mega upgrade?

The older Q7 and Phaeton had a mechnical pedal instead.

Attachment 17651

Attachment 17652

Attachment 17653

Snap, for your perusal, here is mine.
We have a 2004 3.0 TDI

Address 53: Parking Brake Labels: 4E0-910-801.clb
Part No SW: 4E0 910 801 D HW: 4E0 907 801 B
Component: EPB A4EC0230 H03 0230
Revision: --H03---
Coding: 0000221
Shop #: WSC 00196 067 57207
VCID: 204FCCB5F3268E46AA-8074

Thanks so much.
Looks like there were no SW updates after ours.
I bought a module for an D4 a8 4H0907801H
It did not work at all - no communication with it on CANBUS.
Now waiting for a D3 unit from USA.
Would still like to try an A6 ECU without the hall sender function.

Here is my ecu details:

-------------------------------------------------------------------------------
Address 53: Parking Brake Labels: 4E0-910-801.clb
Part No SW: 4E0 910 801 D HW: 4E0 907 801 B
Component: EPB A4EC0230 H03 0230
Revision: --H03---
Coding: 0000221
Shop #: WSC 00046 000 00000
VCID: 20486A13F3B91346B1-8074

No fault code found.

-------------------------------------------------------------------------------

Here is mine Snap +++

-------------------------------------------------------------------------------
Address 53: Parking Brake Labels: 4E0-910-801.clb
Part No SW: 4E0 910 801 C HW: 4E0 907 801 A
Component: EPB A32C0220 H02 0220
Revision: A32C0220
Coding: 0000731
Shop #: WSC 00654 210 91809
VCID: 1F4D0CE9CE3222C667-804A

No fault code found.

-------------------------------------------------------------------------------

Thanks chap - still waiting for my spare module to be delivered from USA.
Seems 0220 /0230 is the SW version.
It's also printed on the casing and (year 2007-) 0230 was the latest version until end of D3 production.

Well, I recieved the spare part yesterday and fitted it.
Exactly the same codes and behaviour, so looking at wiring loom or swapping calipers from one side to the other to see if the issue moves. I don't want to take the motors off as the casing split last time I did that on my old one.

You might want to do a continuity check on each of the pair of twisted wires from the Brake ECU to the Caliper to see if that throws up and issues - I ended up replacing each twisted pair with my car to all four corners as the casing on the wire was intermittently cracking and exposing wires which then touched and threw up faults at all sorts of times! My only difficulty with that is that I cant see that issue throwing up that particular fault but certainly continuity check the appropriate wires concerned

I spent a nearly a year chasing my tail with EPB issues, I swapped the ECU for a used "good" one, chased wiring, banged my head against a brick wall.

I got to the stage of buying a couple of litres of unleaded and a box of matches, but decided out of desperation to buy a new ECU from the local dealer, cost a few hundred quid but worth every penny.

I uded the petrol in my lawn mower and kept the matches dry for another day :ROFL:

Never saw the issue again, not sure if it re-occurred but mechanico-lee would know!

FWIW and from memory the motor each side is driven by a TRIAC in the ECU, which when too much power is put through them then overheat and die a slow death. As it happens, a failing motor draws enough current to cause this, especially if not replaced quickly. I think some opened up the ECU and replaced the faulty components, I suspect others replace and then out their old "good" ones on ebay :Confused:

Good thoughts. Today I ordered a new connector and 4 repair wires.
Rediclous £42 at TPS - I didn't pay so may not go back and instead just get them online. £1.99 delivered from China for the connector from aliexpress with the wires, seals and pins assembled, but alas with thinner wires so would need to upgrade them. I need 2.5mm2 and 4.0mm2 but these are 1mm2 and 2.5mm2. I can get the correct pins from ebay for about £10 for 10 each size and use my own wire.

Good point about faulty ones on ebay sold as working as they were people's old originals- I did think of that and sought one from a car being broken up rather than a one-off sale.
I did test continuity the lazy way via the resistance of each side's pins for hall sender and motor matching left and right but I hope to be able to make up a test cable with my connectors and pop the 4 pins from the ECU plug and replace them with those of my test lead and try this before working on the loom.
Thank you

Attachment 17756


7D0945527 grommet
1J0919231 flat contact housing, connection piece, servomotor 4 pin X;2;2

2.8 mm female flat terminals
000 979 021 (000979021): 0.5mm wire
000 979 133 (000979133): 1.0mm wire
000 979 225 (000979225): 2.5mm wire x2 xxxxx

4.8 mm female flat terminals
000 979 023 (000979023): 0.5mm wire
000 979 135 (000979135): 1.0mm wire
000 979 227 (000979227): 2.5mm wire
000 979 306 (000979306): 4.0mm wire x2 xxxxxx

If anyone's interested for future reference, they are also the parts needed for adding extra blade fuses to vacant positions on fuseholder.

2.8 mm terminals are for the smaller ATM fuse.
4.8 mm terminals are for the larger ATC fuse.

Snap , do you have an amp meter or inductive amps clamp or multimeter that can manage up to say 30 amps

Snap, you've got a PM +++

High Lee yes, but is doesn't work unless you seperate out a single wire, can't do + & - in the clamp together.


A bit of sun and no snow so I took both calipers off today.
Left and right are not physically interchangeable (I was wrong when I said that earlier) but are electrically identical.
I swapped them over and blocked the piston with a block of wood. The problem stays on the same side so definitely wiring problem.

Attachment 17786

I cut into my previous repair which was still perfect but the damp wire had continued to corrode further along. (black wire syndrome)

Attachment 17790

Attachment 17788

Attachment 17789

Very bad, I cut it back as far as I could and cleaned and de-oxidied with deoxit and scraping with a scalpel. Soldered on new wires and connector, but same errors. I think the wire is too far gone.

Attachment 17787

I have looked at the loom and I can see branches split off to speed sensor, height sensor and EPB. They are all moulded into one tough insulated assembly that converges and disappears as one thicker rubberised cable up behind the rear wheel arch liner.

My options are to install a new partial loom but not sure how it fits, cut existing and splice in a partial used loom or to make another cable - EPB motor plug with 4 wires and wrap it as a loom all the way to EPB module and pop out the existing 4 and insert new ones.
Thinking about it.

Wow, 3 months and a week later, I finally got chance to fit my new home-made partial loom and it works! Phew. Also had to pop out the piston and replace the dust boot as that had ripped somehow (on left and right sides)

Had to remove the rear wheelarch liner so cleaned that all above and behind it with pressure washer. Found the accululator on the air shock was a bit rusty on the seam so put some anti-corrosion wax on it.

A couple of panel clips broke, the part number is 4D0807300

Attachment 18279


Attachment 18280

New cables were insered into gland just behind damper which is next to plastic vent in the side triim of the boot interior and can be reached by hand and pulled - only had to remove navi/TV access panel.
Then routed behind plastic boot slam panel trim and to EPB control unit uner the battery.
When I popped the pins out of the large connector on the EPB ECU, the contact was a different design that those I had bought, so I cut and soldered to the existing wires. (two thick and two very thin for the hall sender)

Did you ever get around to testing an A6 EPB module before diagnosing the wiring fault? A lot of A6 parts (4F0 part numbers) seem to be interchangable with A8 ones. I think this would be more likely to work than a module from the D4 A8.

I've also had a couple of intermittent parking brake faults in recent weeks. It's still working correctly now so I'm hoping it was just due to the cold weather as previously mentioned.

If I ever need to replace the module (or motors) in future then I'll try an A6 one. The 2-pin motors are also much cheaper.

Thanks didn't get wound to getting an A6 module, still trying to sell the 4H one :( If I see a really cheap one I might try it. The 2pin motors are about £30 on aliexpress!

All these problems could have been avoided if 10 years ago, West London Audi had followed Audi repair procedures.
Instead, they nicked off a bit of insulation on all 4 wires to the EPB motor cable presumably to probe with a voltmeter - and put a bit of tape over their damage. This allowed moisture in over the years that rotted the conductors.

Attachment 18285

Old thread I know but just wondering.. so on this note I recently purchased a Passat electric motor for the rear caliper and it was only around £25. It too had only two pins and the connector is physically mounted to the actual motor (as oppose to a wiring loom with the connector on the end of the loom, as is with the A8 D3).

I would be curious to know if I can somehow customise this to retrofit it to my rear caliper. What are the additional 2 wires for on the D3? Does anyone know?

thanks

Maybe someone who can read current flow diagrams can assist. Here is the relevant diagram, and from it I can see that the two heavier wires go to the actual motor. Not sure about the other two.

http://forum.a8parts.co.uk/attachmen...1&d=1562759564

There's not really any info there to read, except that the symbols imply that there is some electronics involved. The ECU terminals are marked S+/S- (as opposed to the M+/M- of the motor terminals), so my guess is 'S' stands for signal and that they provide some sort of feedback. It could be a serial data link (probably unlikely), PWM (possible) or a simple 0-5 volts signal. I'd start by putting a (DC) voltmeter across the wires to see how it changes. If that's inconclusive an oscilloscope should reveal what's going on.

The fact that there are only 2 'signal' wires would lead me to suspect that it's just a simple voltage/resistance measurement, anything more sophisticated would require a power connection too. While it's possible to send power and data over the same wire, I think it's rare to see that in automotive applications.

That other symbol is for a transistor. Probably part of the control mechanism for end of movement in some way?

I'm sure this was discussed previously, possibly on another forum, but I know I had similar thoughts when I had a D3 (5 years ago)....

From memory, the A8 had a hall sensor in the motor, that the passat does not.

The motor is driven by a big transistor in the control unit (one per side) that had a tendency to burn out (or end up with a dry joint).

On my car, I replaced one caliper (refurb from ECP) which was gummed up, a month or so later the other failed with the same issue so that got swapped also, but I couldn't get the fault to clear which was resolved by buying a brand new control unit - total cost at the time was ~£700....

if you want to use the passat motor, you may also need to look at the passat control unit, but that then leads to questions about broader integration, so was in my view at the time more hassle than it was worth.

I think the transistor symbol is generally used these days to symbolise any type of electronic device/circuit rather than a single bipolar transistor, like it used to do (back in the days of single transistor ignition coil amplifiers, for example). The J540 ECU in the diagram has the same transistor symbol but no doubt contains numerous components and several integrated circuits.

I think the other wires are to do with determining pad thickness(wear).
When I stripped my calliper down to refurbish, I didn't see any other way that the car can determine pad thickness other than how far the motor mechanism moves in relation to the pad thickness that you are supposed to program in via vcds on installing the new pads.

The two thin wires are to count the revolutions of the motor and so calculate the change in pad thickness (wear) there is a hall sensor in the motor housing and these wires connect to that, it gives a small 'blip' signal when a magnet passes by. (A bit like ABS wheel speed sensor I presume).

As it was not very reliable, they went back to wear sensors in the pads on other models.

There is a thought that the A6 EPB module is the same except for ignoring this wear input, therefore may be more reliable and you can just rely on your eyes for the pad wear.

Hi Snapdragon

Does that mean then that it could be entirely possible to still use such a motor and simply hack the connector such that the additional two wires are not used? :rolleyes::rolleyes::rolleyes:

If so, then like you suggested, the pad wear could be left to just eyes only?

Someone was going to try it but if they did I missed the results - not aware of anyone trying it - so it is just a theory.

It was definitely discussed here previously on the forum as a possible solution, and may have been paulrstaylor as he mentioned above.

Sounds like it would be quite straightforward to make an emulator (powered by the motor wires), generating the required sensing signal while the motor runs. Might take a bit of research and testing though.

Bumping old thread...sorry..

The two additional connections are to a hall sensor in the motor assembly, they count the revolutions to "Sync" left and right callipers AND measure the pad thickness.

I have a failed one...its a pain in the Arse, it still works but the sides are out of sync....looking for a replacement motor as we speak!

If anyone has a faulty caliper motor, they are about £46 delivered now...
https://www.aliexpress.com/item/32987565843.html?
Dust boot, piston seal and guide pin boot kits are about £15 on ebay.
Red rubber grease £3
There's very little else that can go wrong from wear and tear so this should bring down the cost of fixing up a dud rear caliper up to around £65.
The pistons can usually just be cleaned up with 1200-1500 wet and dry gently polished all over in a circular motion.

Attachment 22292

Good work that man!
That's excellent news. . . . +++:D
Almost worth sending for a pair ahead of needing them and keeping them "in stock". . . I note you also get additional discount for ordering a pair

I was certainly looking at the various Audi EPBs with an idea of repair!

http://forum.a8parts.co.uk/showthread.php?t=13431

I've "repaired" my left EPB at least 3 or 4 times. Taking the back of the EPB, freeing up and cleaning up the crap from it, sealing as best i could and putting back on. Always the left one!!!

I hit the same issue again about a week back and bought one of the Chinese ones off ebay ( https://ebay.us/4OKGtN )as to be honest the plastic casing of the old one was knackered and crumbling. It came with the big O ring seal and a pair of hex screws that are too small and the odd circlip that fits on the piston part where the actuator fits in

I swapped it over. My pads were low so i swapped on a spare pair of those. All went pretty well and things were quieter and seemed to work ok. I still had a pad error but often that sorts itself out.

However on getting home, the car checked the brakes and it errored again.

Today I popped it back off and tried the adjust the brake to the mid point and tried again and actually I'm a bit stumped.


The motor turns, the actuator is the right size, it fits nicely and sounds better, but it seems to run too long and then error. The ampage appears a bit higher but nothing drastic the left is 0.5ish more than the right.

I did pop the old one open and the motor part is potted into the case or i'd have swapped bits over.

I'm a bit confused to be fair why it seems to run longer than the other side and thus error

You need to use vagcom on the rear EPB to tell the brake module you are changing the pads for new and also re-enter the new pad thickness as measured. This is so that the brake module knows that the pad thickness has changed and where to start in assessing the remaining thickness +++

Yeah.....I've got vagcom/odb11 and i can play with the thickness, open/close the epb, do the test.

That's how i know the left is running way longer than expected.

I've tried various thicknesses of pad, but the error says left disc not reached which is curious as i know it does eventually get there.
I think i'm going to try and referb the old one again and swap that on and see what i get from it.
It feels like the two motors are out of sync or not recognising things.
My discs are on the thinner side (i'd swap but getting hold of a pair atm is probably tricky) and with new pads on that side they should easily compensate.

Most motor factors are open and will deliver (ECP etc). If you want genuine Audi then only TPS will be open but they will only deliver to a registered business address.

I actually run a small manufacturing business so could get round that, but the Audi is more a workhorse than show car. I ended up furloughing myself and my two guys on Friday, because lack of work, struggling with supplies and all sorts. The Audi is safe on charge in my factory.

I tried the old EPB yesterday after a good clean out, taping and sealing and it made no difference. Super long run times on the left side still.

I've ordered a pair of Mintex discs to home which should turn up at some point this week and then I'll go in a fit to both sides, check the pads balance up and try again with the new EPB and see where I get to.

I've got the Jeep to run around in and it's not like I'm going far anyway :ROFL:

Had another go at this today. The discs turned up and I fitted them to both sides, checked the pads were even and balanced.

No joy. The left still runs and runs. I popped the left side off again and tried the old motor and same thing. I had a C clip in the new motor parts, but never bothered changing it. It goes on the piston side around the large star drive slot. I took the old one off, cleaned things, checked that things were freely moving with a star drive and, yes the internal (worm screw?) seems to work fine. I wound it in and checked the caliper and made sure that was moving reasonably and cleaned things a bit too.
I put it back together but left the wheel off and ran the test.....It seems like the motor isn't engaging and turning the internal drive....But i can't for the life of me figure out quite how / why!

Both the new and old motor have the wobble drive thing, which seems like some form of clutch and allows the Star drive to engage and disengage and it just doesn't seem to do it in practice.

It's all a bit odd and i'm not entirely sure quite what to do next....I guess there is the option of a whole new caliper perhaps....But it seems a lot of hassle and expense for something that in all essence appears to work, but just doesn't!

I'm probably going to go back into work and do some more testing, probably try with the motor off and see if that resets some things.

I could try something interfacing between the star drive and the socket in piston. I was also wondering on using two circlips to maybe bring the interface back out a bit. I could always open the old motor back up and push the mechanism forwards, but I'm not sure how comfortable with these thoughts, particularly being in the brake area, despite rarely using the parking brake.

I guess the other option is replace the whole shebang:

Ebay gives a Chinese full copy at £143, but the delivery times atm probably scratch that and you always have the is the copy any good factor.

There's a second hand option from our sponsor, which is £150 and a couple of days delivery. No specific 4.2's and most are older 3l's but I believe that it's all the same actual model. A little worry in longevity perhaps, but once the old one is off and stripped down I can check it out a lot better and referb it pretty cheaply and I have 1-2 motors etc!

There's also re-manufactured ones for £150 and also a few days delivery. However there's the hassle of £100 deposit and then sending the old one back and IF mine qualifies etc too

I'd like to get my normal driver back and so i can easily carry on my Post Apocalyptic make-over on my Jeep