Auto Hold retrofit – ABS plug pin‑out Audi A3 8V (2020, DPCA, 35 TFSI)

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DaywaIker313

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Hi all,

I want to retrofit Auto Hold / Hold Assist on my Audi A3 8V and need some help with the wiring and coding.
Car details:

  • Audi A3 8V, model year 2020
  • 35 TFSI, engine code DPCA, EA211 evo
  • Electronic parking brake from factory
  • ABS/ESC unit: ATE MK100, part number 5Q0 614 517 DN
I already have:

  • Auto Hold button
  • Wiring / repair terminals for the ABS connector (7L0 973 047, 47‑pin)
What I am still missing is reliable information about the exact pin assignment for Auto Hold at the ABS connector and some real‑world experience with the coding.

My questions:

  1. To which pins on the ABS connector (T46a/T47) do the wires from the Auto Hold button need to be connected on this MK100 unit (5Q0 614 517 DN)?
  2. Does anyone have a confirmed pin‑out diagram for this specific ABS unit, or can at least confirm the Auto Hold input pins?
  3. How did you handle power supply (ignition‑switched +12 V) for the Auto Hold button?
  4. Which coding/adaptation changes in module 03 (ABS) and in the EPB module were required (byte/bit info or VCDS/OBDeleven screenshots would be great)?
  5. Are there any known differences between pre‑facelift/facelift or different ABS part numbers that I should be aware of before I start repinning?
If anyone has an installation guide or wiring diagrams specifically for the A3 8V / MK100 (e.g. Kufatec, Dandav, Upgrademycar kits), a pointer or the relevant pin numbers would be highly appreciated.

Thanks a lot in advance for your help!
 
T6p/3 brown/gray connects to T46a/32 (ABS)
T6p/1 green/yellow connects to T46a/23 (AVS)
T6p/5 brown connects to T10l/6 (parking brake button)
T6p/4 gray/white connects to T10l5 (parking brake button) which leads to both T20/5 (button for tcs/stability) and T73c/62 (BCM)
T6p/2 red/green connects to fuse holder C SC34

Coding is easy but the information online is incorrect/incomplete/confusing:
Coding ABS (details here: https://www.audi-sport.net/xf/threads/296879/page-3#post-3792193):
Byte 23 enable bit 0
Byte 25 enable bit 0 and disable bit 1 (see detail in the link above)
Byte 28 enable bit 4

Adaptations ABS (using VCDS):
AUTO HOLD functional status, last setting
AUTO HOLD functionality, active

Monitoring of functional lights-Indicator light in AUTO HOLD button Keep it at 7

Adaptations ABS (using ODIS Engineering):
[VN]_Autohold_functional_status:
[LN]_Personalized_settings: [VN]_Last_setting

[VN]_Auto_Hold_Slide_Detection:
[LN]_Auto_Hold_Slide_Detection: [VN]_activated

[VN]_Monitoring_of_Function_lamps:
[LN]_function_lamp_for_auto_hold_button: 7

Only difference I know with the facelift ABS module is that it is capable of emergency braking when automatically parking with PLA 3.0 (custom dataset!!)
 
Last edited:
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FPSUsername said:
T6p/3 brown/gray connects to T46a/32 (ABS)
T6p/1 green/yellow connects to T46a/23 (AVS)
T6p/5 brown connects to T10l/6 (parking brake button)
T6p/4 gray/white connects to T10l5 (parking brake button) which leads to both T20/5 (button for tcs/stability) and T73c/62 (BCM)
T6p/2 red/green connects to fuse holder C SC34

Coding is easy but the information online is incorrect/incomplete/confusing:
Coding ABS (details here: https://www.audi-sport.net/xf/threads/296879/page-3#post-3792193):
Byte 23 enable bit 0
Byte 25 enable bit 0 and disable bit 1 (see detail in the link above)
Byte 28 enable bit 4

Adaptations ABS (using VCDS):
AUTO HOLD functional status, last setting
AUTO HOLD functionality, active

Monitoring of functional lights-Indicator light in AUTO HOLD button Keep it at 7

Adaptations ABS (using ODIS Engineering):
[VN]_Autohold_functional_status:
[LN]_Personalized_settings: [VN]_Last_setting

[VN]_Auto_Hold_Slide_Detection:
[LN]_Auto_Hold_Slide_Detection: [VN]_activated

[VN]_Monitoring_of_Function_lamps:
[LN]_function_lamp_for_auto_hold_button: 7

Only difference I know with the facelift ABS module is that it is capable of emergency braking when automatically parking with PLA 3.0 (custom dataset!!)
Click to expand...
This might be a stupid question, but when I had the plug in my hand, I had no idea, where to count from :(
 
The numbering is often written on the connector, but you need good eyes to read it (or a good camera).
If you purchased the wiring from AliExpress, you'll have original wiring colors.
If you purchased from overpriced Kufatec, you have white wiring with the pin numbering printed (not ideal!).
 
Thanks, I will try the camera :)

I did get my stuff off AliExpress, rearview camera, auto hold, Sline door lights, and USB connection to the MIB 2 (AA/CP). I could not tell the difference to OEM, but I'm certain, most are OEM. Kufatec is crazy with their pricing. Actually surprising that they still make any money in times like this...
 
If you order wiring from AliExpress it comes in a bag with a sticker on it. You can use a translator app to translate the text (by camera) and see where which wire connects to.
Sometimes the translator gives odd translations, e.g. for blue/red wiring it can translate to "police".

Sometimes the aliexpress harnesses aren't accurate. I found out the following:
- B&O retrofit wiring harness doesn't follow the original wiring coloring (I assume because there are way too many wires, unlike most easier retrofits).
- Auto dimming exterior mirrors wiring harness have incorrect connectors (but do fit), besides that, the harness bypasses the door module with a separate connector. Original style brings the interior mirror to each door module, and each door module connects to the mirror glass.
- Auto dimming interior mirror wiring suggest you to connect a wire to the reverse bulb signal, but the A3 has a separate pin on the BCM for the interior mirror.

But the sticker on the bag is usually the key, and it really helps to cross check with the original wiring diagram of the car to confirm things.
 
Thats insightful, but I have already disposed the bag...

I go with the colours of the wires, since they have the colours that you said.

The cables are already run to the engine, just need to plug it in and do the coding, I think I only have one shot at this, as it looks impossible to get wires out from the plug again, there is this rubber seal, and no way to reache the release pins on the plugs...wish me luck!
 
Keep in mind that the abs connector has plastic blanking pins inside which you need to remove after moving the locking tab.

You'll need depinning tools if you want to redo the job, they're quite cheap on amazon (the ones that look like a bunch of keys), but I assume proper depinning tools are a lot better. A set of 30 or so screwdriver-like depinning tools in a case cost around 35 euro on AliExpress.
 
Oh wells, I tried, but I was not able to get the pins all the way in, they are probably not the correct from factor for the crimp pins. I have a depinning set and tried to get it back out, however, the cable snapped...I guess that's it now, the pin is still inside, and with no way of getting any leverage on it to pull, I think this plug is toast...

need to see what I can do to fix that, I really don't want to redo the entier plug
 
Resurrecting this thread.... I've just taken a punt on a cable set from aliexpress after seeing the Kufatec prices.... EUR56 for shipping to UK!!!!

I need to source the switch now, but my car is a cabriolet so I need the dual-purpose button like below. Does anyone know the part number for this to help me track one down?

43734-11-schalter-fuer-bergabfahrassistent_1280x853.jpg
 
Left hand drive:
Without chrome 8V7959727B
With chrome 8V7959727C

Right hand drive:
Without chrome 8V7959727F
With chrome 8V7959727G

Current price at the dealer is €95,69 without tax applied.
 
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Thanks for the info @FPSUsername i have now ordered two switches off ebay and neither are any good First one was faulty, the second brand new but illuminates red when I need one with white illumination.

I've been looking for part 8V7959727G as I want RHD with chrome but this seems to be red illumination, do you know if there's a different part number for white?
 
Facelift model (white LED):
Left hand drive:
Without chrome 8V7959727K
With chrome 8V7959727L

Right hand drive:
Without chrome 8V7959727P
With chrome 8V7959727Q
 
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Since you already have the PFL one, just swap out the LEDs. The size should be 3528.

I used red WL-SMTW SMT Mono-color TOP LED Waterclear Size 3528 leds for the MHI2 control panel for retrofitting MHI2 on my pfl a3.
 
Closing this one off, I finally completed the retrofit this weekend!

For future reference if anyone else wants to retrofit to a facelift cabriolet, you will need one of the switches part numbers from @FPSUsername above. The one ending Q was correct for me. It's the most expensive part of the retrofit.
Facelift model (white LED):
Left hand drive:
Without chrome 8V7959727K
With chrome 8V7959727L

Right hand drive:
Without chrome 8V7959727P
With chrome 8V7959727Q
Click to expand...

You can use a cheap wiring harness from aliexpress and it doesn't need to be cabriolet specific. One like this will be fine (don't buy one with the wrong button) - mine was about a tenner.

3A4C02C4-B02B-463A-BA91-96516AA4A2B7_1_105_c-optimized.jpeg


Use a depinning tool to carefully extract the pins from the red plug like this.
20260516 152812


You will need to keep three wires: yellow+green, red+green and brown+grey. You can separate these from the wires going to the black plug by carefully cutting away some of the cloth tape. The black plug/splitter and the other wires in it can be discarded.

The plug on the cabriolet hood switch that you replace has blank spaces for the wires to be inserted in to, so carefully dismantle the centre console, route the wiring and push the new wires in to the plug until the locking tabs click in place.

20260516 134136


The rest of the installation is as any other guide.
  • red/green goes to fuse 34 (I used a fuse tap for this) and routed to pin 10 on the switch in the centre console
  • green/yellow goes switch pin 1 to ABS plug pin 23
  • brown/grey goes switch pin 3 to ABS plug pin 32
This video shows almost all the installation process on a TT which is almost identical to A3/S3 and gave me a lot of tips, especially the coathanger-through-the-bulkhead trick.


View: https://www.youtube.com/watch?v=dzy4YL_5IpQ

For troubleshooting:
  • red/green supplies +12V when ignition is on, check this
  • green/yellow is the auto-hold switch, powered by red/green, pressing the switch can be monitored in OBDeleven under 03 Brakes -Live data - Auto hold
  • brown/grey is the indicator lamp, which will come on when this line is pulled to ground
When I first completed the install and coded it up I still had the "warning lamp open circuit" error in the dash and traced it back to the brown/grey line. TOP TIP: the ABS plug is DEEP and the pins need to be pushed a long way in. I hadn't pushed it in far enough, thought I'd heard the click and couldn't seem to pull it back out, but still it hadn't gone far enough in and wasn't making contact.

Coding is all as per other guides except there was one minor difference on my car:
  • Byte 08 was 89 changed to 8B
  • Byte 19 was 91 changed to D1
  • Byte 23 was 76 changed to 77
  • Byte 25 was 41 unchanged
Security codes and adaptations as per other guides, and you're away!

I hope this gives someone else the confidence to give it a go. It's quite straightforward once you know what needs to be done, as far as retrofits go! Worst part is faffing around in the footwell with trim, glovebox, carpets, trying not to snap any important tabs! TOP TIP: Lego brick separators make great trim removal tools :)
 
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