Naughtie

I need a little advice.

I just performed a rear brake pad & rotor change. Instead of using a VAG COM I used the "12 volt" method to retract the parking brake, which worked well enough to get things started.

During reassembly of the drivers side, I proceeded in the following order:
1. with the parking brake still disengaged and unplugged (it had been disengaged since the start the brake job) but engine on, I pumped the brakes to reset the piston
2. with the parking brake still unplugged (I haven't touched the passenger side yet), I engaged the parking brake
3. I used the 12v leads to engage the parking brake on the drivers side
4. I reconnected the electronic parking brake cable at the caliper
5. with the car running, I disengaged the parking brake

I've now got a "Parking Brake Malfunction" indicator flashing. My parking brake LED continually flashes. Every time I start from a stop, I get a long warning beep and a "Parking Brake Engaged" message on my MFD.

The good news is that the car is driveable. The passenger side parking brake (which I haven't touched) continues to work as intended. The drivers side that I worked on isn't causing me any problems, though I don't know if it's engaging / disengaging, or maybe just not being used.

I plan to get a VCDS to attempt to reset this. Failing that, I'll probably be looking into opening up and rebuilding the parking brake mechanism, if that's such a thing.

But here's a question: the electronic parking brake appears to be a "dumb" connection, i.e. 12V leads only, no communication. So what problem is the car detecting? The motor extends and retracts the caliper when I apply 12 volts to it. I can hear it "bear down" on the rotor when I apply it in the engaged direction, and I can see it release when I reverse it. So what is the car sensing is wrong?

Naughtie

I'm following up on my own post for posterity's sake. Hopefully this info will be useful to some other forum members or Google searchers in the future. My car is a 2013 allroad but I'm betting this applies to sedan A4 and S5 models as well.

The 12v EPB retraction method I referenced is detailed in a few different forum posts I stumbled across, including here: Rear brake job without needing a Vag-Com - Audi A5 Forum & Audi S5 Forum

...and a video clip of it can be viewed here:
This went smoothly enough as I outlined in my original post, up until reactivating the EPB. Maybe I shouldn't have cycled it back in? I dunno.

What I do know is that for two weeks I drove around with a "Parking Brake Malfunction" indicator, with a 5 second long "beeeeeeeeeeeep" every time I pulled away from a stop, but otherwise the car worked as intended! The brake worked correctly, didn't drag, the hill holder worked, and the car was completely driveable.

I ordered a Ross Tech Hex V2 hoping my condition would be quickly correctable. My diagnostic hit on the following fault conditions:

17403 - Implausible Data Received from Parking Brake Control Module
Fault Frequency: 45
00473 - Control Module for Elect. Park/Hand Brake (J540)
Fault Frequency: 2
68352 - Control module left channel voltage supply
C1012 14 [000] - Open or Short to Ground
Intermittent - Not Confirmed - Tested Since Memory Clear
69888 - Left Parking Brake Motor voltage supply
C100D 01 [137] - Electrical Failure
Fault Frequency: 43
Reset counter: 248
70400 - Left Parking Brake Motor
C100F 00 [137] - -
Fault Frequency: 1
70912 - Left Parking Brake Motor voltage supply
C100D 13 [008] - Open Circuit
Intermittent - Confirmed - Tested Since Memory Clear
Fault Frequency: 17

Trying to do anything with channel 53 - parking brake resulted in an error within VCDS. I don't recall the exact error message.

I was pondering swapping in a new EPB module or a new rear caliper.

But then I stumbled upon a forum post somewhere that suggested pressing / holding the parking brake for 5 seconds at a time multiple times. I tried it, but it didn't seem to do anything. The brakes engaged like normal, but subsequent presses didn't make any parking brake motor noise. The following drive was the same, with my Parking Brake and Brake warning lights illuminated, my parking brake switch LED flashing at me, and a long beep tone every time I pulled away from a stop.

BUT!! the following morning, everything had cleared!! No lights, no beeps, back to normal. I really don't know what happened, but the only thing I really did differently was the multiple 5 second presses. I don't believe anything I did with VCDS had an impact.

So this was a happy ending. I was able to use VCDS to retract the pads the proper way, knocked out the right rear, and got the car all buttoned up free of errors.

I'd really like to go back and try the 12v method again just to figure out what (if anything) I did incorrectly, but... nah. I'm good.

jasontaylor7

Thanks for your posts Naughtie. I have almost the same problem. The difference is the 1487 (or 01487 or 001487) notification/error. See https://www.audizine.com/forum/showt...-7-days-a-week for details but I will copy and paste below in the spoiler in case you don't have access to that site.

I googled "5 second" to try to see your source about the holding down (or was it up?) of the parking brake button. I didn't find the post you are referencing. Can you tell me where that was? I held the button without any benefit I could see.

My guess is that after driving a fixed number of miles, an ABS-related adaptation was done by itself. How many miles did you go during this time before the alarm disappeared?

A steering wheel error also appeared. But it quickly went away. I don't know what to do now.

Any help or ideas would be appreciated. I don't want to just drive it with earmuffs for two weeks because that's illegal here and my girlfriend would kill me before the two weeks is up anyways.
I tried the system test where you put all your weight on the brake pedal and go strait at 13 mph and then turn steering between 90-180 degrees without any luck.

I wonder if the computers are using the clock to keep track of the brake pad levels. If the wear is non-linear it triggers this alert. My clock is at 2004 because the GPS antenna is broken and the setup button seems to be broken. Is there a way to set the clock without fixing the gps using vcds?

jasontaylor7

Naughtie I am not sure I answered your Q or not. There's no need of any sensor wires because the computer can measure current of the two wires as a function of voltage applied.

I got mine fixed. It's become broken again, as I will explain, but I learned a lot so I may as well post to help others as the videos about how to handle parking brake issues can be improved. I saw so much disinformation and overly complex solutions.

First of all the warnings about voltages from ROSS-TECH are wrong. You won't brick your module if you disconnect early from the initialization tests where the parking brakes go on and off three times. All you might need to do is turn the car off and on to reset. Nor do you need any battery charger if you have a good and charged battery in the first place. Indeed many of the functions can be done with the car's engine running, so it's a moot point. You don't really need ross tech tool to fix the parking brake issues anyway. It's such a distraction. The wires go bad and that's the issue. I actually discounted this theory for a long time because my cable seems to look perfectly fine. No breaks I could see anywhere at all. Just bad cable or something strange like an OEM crimp in wires. I still don't know.

But do not follow the advice of this video where someone solders like 6 wires: https://www.youtube.com/watch?v_TniryQZy0s

The better way to handle any parking brake module error is to first independently check the four wires going from the parking brake module to the brakes. This method avoids needing to disassemble any of the trunk, and for the repair it is just one wire to add in via soldering.

First, remove the tool set, jack holder, and parking brake module. Now you have a connector with 8 thick wires/connectors and many small ones:


My right brake was the one with issues so that's the one I know about. The green arrows show where the connector is for the right parking brake module and where to remove the zip tie on the connector to allow you to see where all these wires go as the connector itself can be disassembled. The reason for this is to get a pinout without having an alldata subscription. as they raised prices. But you only need to do this for the left brake as I don't know which two wires it is for those. I think it is pink and brown something but unless someone posts you'll have to check yourself using the following method.

If you need to test your left brake or are curious, to get this info I just peeled back the black sticky tape on the thick wire going out of the right side tire well (behind the trunk liner) and noticed that the brown wire with a white stripe and the yellow wire with a red stripe were the two thick (high current) wires that have to be powering it:



Then I removed the zip tie on the connector allows me to see where these wires connect to:


For the right hand side parking brake wire connectivity test, you just apply 12 volts to the two connectors with both polarities. If there's no sound of a motor or any spark, you really do have an open connection on at least one wire. It's usually the brown wire, but if you want you can run an ohmmeter from the two sides of the wire harness after removing the rear wheel, the rear wheel liner, and the connector to the parking brake. Narrow slices of metal may be helpful to do these tests to avoid bending the connectors, like these:




Once you've verified that the wire harness is bad, can try purchasing a new d-plug. But, I wasn't able to find any. I purchased several and none fit. I purchased this:


But it was too small.

I also purchased some of these:



Don't buy them either, as they also don't fit. See the plastic on the lower left?

This is the only thing that fit:

Hyperlink to ad: https://www.ebay.com/itm/143452238461

This worked great.

Another option if you don't want to wait a long time is to just resolder new wires ones from an old household appliance wire to that. My old soldering gun was not powerful enough. I opened up a new one I had and it could do the job, but it's just not easy to solder copper wires this thick.

Advice: don't bother with the existing wire's entry to the car. There's actually a plastic circular plug in the top of the rear wheel well to remove. Wrap the wire around the brake line supports and apply shoe goo or silicone to prevent slippage. Then you take your solder gun and melt a thick line from the outside to the inside of it allowing room for the new wires so it looks like this instead of being a circular plug:


Thread wires through that and reapply. Here is the inside of that once you are done applying shoe goo or silicon to re-seal it:

For the side nearest the PBM, you just remove a little tape near the connector, splice in the fresh wire using your favorite wire-joining method. Cutting and soldering it is probably the best way as the amount of heat required to get the thick wires is much less if there's only one side cooling it and not two sides. Indeed, my first attempt failed after a day because my solder gun just couldn't get everything up to temperature for these thick wires. Not cutting also increases the risk you melt insulation from the other, good wires in the wire harness.

Once it is installed you will need to cycle the parking brake several times. The reason for this is because the module assumes the parking brake is in the "just open" position. Once you've cycled it 3 times it should works and all the annoying beeps should disappear. It's best to have a friend do this so you can hear that the motor is working correctly. The most likely mistake is to reverse the polarity, and being there to see the electric parking brake flex and make noise is the best way to confirm you didn't get it backwards.

Once you've verified everything is ok it is time to insulate your soldering work. In theory you slip on the heat shrink tubing but as I said these wires are huge and mine either couldn't slip over them or couldn't shrink enough, so I got on some vinyl gloves and placed a huge amount of Shoe GOO on them and manually coated all of the exposed wires. Silicon would also work of course.

Short version: never use ross tech/VCDS as it can go into alarm mode if you do. Order some crimps for testing before doing the repair. If you have any annoying sounds that would make it hard to wait a month, just remove the two 30 amp fuses. Don't take apart the trunk. Test the brakes by hand from the PBM connector. Don't use the existing entry into the car interior from the wheel well as it is behind stuff and already has other wires in it.

If anyone knows where to order the right-sized D-plugs please post the link and I will edit this as soldering under the car isn't elegant.