Autohold retrofit

Dachshund.Power said:

Thanking T-Reguan for the idea, yuyueyuyue for the coding and mckpat03 for the VCDS cable use.

Works well - great feature.

Anyone ever figure out the red/green park light or are we still in the dark on that one? It would be nice, though not strictly required.

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Dachshund.Power said:

Thanking T-Reguan for the idea, yuyueyuyue for the coding and mckpat03 for the VCDS cable use.

Works well - great feature.

Anyone ever figure out the red/green park light or are we still in the dark on that one? It would be nice, though not strictly required.

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n773ph said:

I frequently lurk CT despite being a registered member but I just had to sign-in to thank T-Reguan, yueyue and all the wonderful folks here at CT. Got the autohold switch installed on my '14 TDI this afternoon and it works perfect! I also threw in the euro-spec ESP switch just because I hate blank spots. Only the ESP works, the rest doesn't.

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yuyueyuyue said:

Just got my 2014 Lux working today.

AS ALWAYS, YOUD DON'T HAVE TO DO IT, BUT IF YOU DO, DO IT AT YOUR OWN RISKS. I TAKE NO RESPONSIBILITY IF YOU BREAK YOUR CAR OR OTHER ISSUES ON THE ROAD.

I'm going to post how I find the way to enable it, just so others can correct me if I did something wrong.

I have it enabled, but I don't know if there are any other codes that I need to change to make the car behave the same as to the factory setting. I've done a little test, everything seems fine, but for now, mine doesn't switch to parking brake after 3 minutes on ABS. I'm thinking maybe it's not time based, it could be temperature based from the ABS pump.

Anyways, I started by collecting publically available ABS coding for all T3's all over the world. Divided them into 2 groups. Group 1 is for cars with auto hold coding, basically ROW T3, pre-2012 US T3, and 2012 Hybrid (OP's coding since OP’s car is plug-n-play, the coding must be there). Group 2 is US T3 after 2012. Then compared coding for discrepancies. I'd like to have a bigger data pool, but after a day of searching online, these are all I have so I decided to go with what I have.

The code I'm looking for needs to satisfy 3 criteria,

1. Needs to be mutually exclusive between groups. The code cannot re-appear in the other group.
2. Needs to be greater in group 1 than in group 2 since we are adding a function.
3. Better to be consistent.

You can see only byte 16 satisfies this condition. I know there might be other differences between different years, but I decided to try the coding now, if it doesn't work, I can change it back and do more research then. Risky time saving move…

View attachment 103417

Surprisingly, it worked! Now I’m going to drive slowly and avoid traffic for few days to see if the car behaves normally.

Here’s the steps in VCDS.

Step 1. Hit start/stop without pressing the brake pedal, engine should not be running.
Step 2. Open up channel 03 for ABS
Step 3. Fire up the long coding helper, no security access needed.
Step 4. Select “Byte 16”
Step 5. Change the coding from “01110011” to “01110111” in the binary area, don't forget to hit "enter" on your keyboard, then Byte 16 should read “77”

Step 6. Save it
Step 7. Now your TC, ESP, and ABS lights on your dash will flash, don’t worry, turn off the car.
Step 8. Start your engine, the 3 lights should be gone.
Step 9. Foot on the brake, click on seatbelt, you should be able to enable Auto Hold now.

View attachment 103409


AGAIN, I'm still testing this coding, please proceed with caution.

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Dachshund.Power said:

@yuyueyuyue-- did you ever get the red/green park light in the gauge cluster to work when auto hold is in use?

I seem to recall you looking into that a while back.

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T-Reguan said:

Ok boys and girls, it works!

Here is the promised DIY:

First things first. Disclaimer: This mod is for educational purposes only. I am not a VW tech or it's official representative. I am not responsible for any damages or malfunctions. DO IT AT YOUR OWN RISK. I am simply sharing my findings but can not guarantee it's proper function. You must check with VW to make sure your vehicle's hardware will support this mod. If you do this mod you take full responsibility for ALL and ANY consequences.

Ok, here it goes:

1- remove the trim. I have a trim removal kit that I bought a while back which came in handy on a few occasions including this one.

2- Open an ash tray first. Pry the wood trim open by inserting the thinnest tool in your set between the console and the trim. Push it as deep as you can, then carefully pry it up on both sides (front and back). Pull it forward a 1/2 inch, then lift up.

3- Pull up the gear shifter trim and separate it from the wooden trim then turn and push it under.

4- Disconnect all electrical connectors. Remove the wood trim and flip it over.

5- It took us a minute to figure out how to remove the switch without breaking anything. The switch is held by three clips, two on each sides and one in the back (the stubborn one). The two side clips unclipped fairly easy but the back one needed to be pulled to it's limit to release, be careful not to brake it. As soon as you undo the third (back) clip you can push the switch up and out.

side clips


back (stubborn clip)

6- Push the new switch in. Reconnect all the harnesses. Reassemble the trim and voila, you're done! Yes, you guessed it correctly, no VCDS changes required! This is a truly plug and play mod at least for a 2012 MY. I am not entirely sure if VW kept the same ABS hardware past 2012 MY for an "autohold" to work. Autohold depends on a proper ABS unit to work properly.

You must be buckled up for an autohold to work. Press the button and the switch will light up yellow. When you come to a COMPLETE stop you can release the brake pedal and it should hold (works in forward and reverse). If you unbuckle the "autohold" will disengage and the parking brake will engage. Please educate yourself and get familiar with this feature before trying this on a public road. Have fun!

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