A7 C7 Auto Hold Retrofit

[a4android]

I have a bad knee, tired of holding the brake pedal while waiting for a traffic signal, so I did this.
No need to run wires all the way to the ABS unit from the centre console. All 4GX comes with this wiring factory installed. Nevertheless, note that this was done to 1AT PR code ABS module. If you have 1AS ABS module, it may still work, but it may stressing your ABS unit slightly more

DISCLAIMER

YOU DO IT UNDER YOUR RISK. I AM NOT RESPONSIBLE FOR ANYTHING. NO GUARANTEE.

FYI. My ABS control unit is Part No SW: 4G0 907 379 G HW: 4G0 907 379 G Component: ESP PREMIUM H09 0250

Part required
:4g1927225b
A cheap one from Aliexpress or eBay will work.

Procedure
- lift gear shift boot cover
- lift MMI console
- Unplug parking break button connector
- replace existing with 4g1927225b
- assemble back
- get a coding tool(VCDS, VCP, ODIS-E)

Select Address 03 (ABS)
Access authorization -> Enter access code 61378
Coding -> Byte 8, Activate bit 4, 7 and deactivate bit 6.

Now, if you use VCDS, you wouldn't be able to tick a box in long coding helper.
So you need to calculate Byte 8's HEX value.

For example, my original ABS long coding is
44A70F0122E5F0804B00
and 4B near the end is Byte 8.
HEX 4B is Binary 01001011
Changing bits to 10011011
Converting binary 10011011 to HEX is 9B
So my new long coding is
44A70F0122E5F0809B00

https://www.binaryhexconverter.com/hex-to-binary-converter

DO NOT JUST PASTE MY ABS CODING TO YOUR ABS CODING.
JUST DO THE REQUIRED MATH(IT'S NOT EVEN A MATH) AND CHANGE ONLY REQUIRED VALUE.

Enter the coding and you will get immediately TPMS error.

Just restart the ignition and it should go away.

Enjoy!

- from the RSNAV guy(the infamous one with terrible communication skill)

[briceportier]

wish it was this easy in the A4...

Sent from my SM-G965F using Tapatalk

[Chiromikey]

My hero!! Will install my button and do the VCDS coding ASAP! Can’t believe Audi deletes this option for North America and I’ve been searching for this retrofit since I got this car a month ago so thank you!

[a4android]

Opps, a mistake found.
Stand by for the correction.


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


Corrected.

[acamposac1]

Great job! I just purchased the button. Now to wait for it to arrive...

[Nully]

Ditto, waiting for the switch!

[briceportier]

Just bought a cheap 8K1927225DWEP on aliexpress:
https://s.click.aliexpress.com/e/bsFF0q9j
I'll decide once I have it if I go for the retrofit or not...

Sent from my SM-G965F using Audizine mobile app

[acamposac1]

Just bought a cheap 8K1927225DWEP on aliexpress:
https://s.click.aliexpress.com/e/bsFF0q9j
I'll decide once I have it if I go for the retrofit or not...

Sent from my SM-G965F using Audizine mobile app

Not sure if that will fit the c7. The p/n is different and on the product page it doesn't say it will fit...

[briceportier]

Not sure if that will fit the c7. The p/n is different and on the product page it doesn't say it will fit...

Yep, sorry... that's for my B8.5 and you guys drive C7s...

Sent from my SM-G965F using Audizine mobile app

[wuplur]

Just checked and mine is 1AS with module 4G0907379S. Verified my managers vehicle is a 2016 A7 and has 1AT but same ABS module. Thoughts?

[a4android]

I think it's still going to work.
I see only one hardware revision for ESP9 PR for TDI whereas there has been multiple revision for my TFSI ESP PR.
I retrieved the coding from TDI anyway. Also, I don't think TDI ABS system is weak compared to TFSI considering engine weight.

[wuplur]

I think it's still going to work.
I see only one hardware revision for ESP9 PR for TDI whereas there has been multiple revision for my TFSI ESP PR.
I retrieved the coding from TDI anyway. Also, I don't think TDI ABS system is weak compared to TFSI considering engine weight.

Looks like the TDI does have a smaller front brake setup than the TFSI but I cant imagine it would make a difference for the mod. Initially I thought it applies the parking brake at a stop but that would require coding in 53 not 3. So at a stop it applies pressure to the front brakes?

[Chiromikey]

Looks like the TDI does have a smaller front brake setup than the TFSI but I cant imagine it would make a difference for the mod. Initially I thought it applies the parking brake at a stop but that would require coding in 53 not 3. So at a stop it applies pressure to the front brakes?

Every Auto-Hold equipped vehicle I’ve been in applies front or both and never the parking brake. I’m sure this is no different.

[magn2o]

Hmm.. anyone know what package brings 1AT? I just checked the PR codes on my 2018 A6 Sport 3.0, and it, surprisingly, says 1AS.

[a4android]

I have 1AT and ACC.

As far as I know, 4g(c7) esp are all bosch's 9th generation abs module. Seems tfsi and tdi abs module get merged into one for facelifts as early tfsi modules are several. Since its technical spec is unknown for each unit we don't know exactly what's the difference between 1at and 1as, but all esp 9 are premium so i assume over heating isn't really issue like esp8 found in B8 cars.



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[a4android]

Anyway, i know in Eu, and korea there are many cars with Auto hold without ACC.
So I assume 1as, 1at difference does not play many issue in c7.

Nevertheless I do ask more attention to cars with the factory trailer hitch as the coding above is from vehicle without trailer hitch. Auto hold is not supposed to work when there is a trailer behind.

Frankly, I do not know of detail for what bit 4,6,7 do in byte 8. Nevertheless, byte 8 stuff is known safe to work with.

I know first byte is about engine type and then trany follows but i have no idea about all other bytes and do not recommend alter it.

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[wuplur]

I know my coding and my managers coding were pretty different from a4android.
2016 A6 TDI 47A79641E2E569821B00
2016 A7 TDI 47A7964BE2E569D21B00

Her A7 does have ACC if that makes a difference.

[phaphaphooey]

With this mod is the auto hold status persistent or do you have to reactivate it every time you turn the car on? In other words, will it "remember" if you had it switched on from your last drive and remain activated through a power cycle? It bothers me very much that the auto high beams are not persistent and must be reactivated every time. I am hoping this is not similar.

[a4android]

@wuplur

I Guess,
47 Engine Type, A7 Tranny or chassis(?), 64 Unknown, 1E Unknown, 2E Unknown, E5 Unknown but fixed, 69 few basic settings, 82 Unknown, 1B Basic settings for optional features, 00 - unknown reserved(?).
So your byte 8 is 00011011 so just turning on the bit 7. Thus 9B.

47A79641E2E569829B00

[a4android]

With this mod is the auto hold status persistent or do you have to reactivate it every time you turn the car on? In other words, will it "remember" if you had it switched on from your last drive and remain activated through a power cycle? It bothers me very much that the auto high beams are not persistent and must be reactivated every time. I am hoping this is not similar.

for your C7.5 RS7, there is coding to make it remember.
For C7 PFL cars, I think K-electronic or Kufatec is selling memory module for the auto hold. It's a separate in-line box for preface lifts.

[hikerneil]

Would anyone in their right mind really do this to their $70K Audi? Disclaimers, oops - I just noticed an error, no guarantees, etc........... yikes! Talk about rolling the dice! Good luck.

[Delfin]

Just ordered the switch.

[phaphaphooey]

for your C7.5 RS7, there is coding to make it remember.
For C7 PFL cars, I think K-electronic or Kufatec is selling memory module for the auto hold. It's a separate in-line box for preface lifts.

I attempted to PM you but it will not allow me to as I assume you have the functionality turned off here on the forum. Would you be willing to share the coding to make the Auto Hold state persistent? Without explanations on the long coding for this platform in VCDS I find the long coding to be a bear.

[a4android]

Would anyone in their right mind really do this to their $70K Audi? Disclaimers, oops - I just noticed an error, no guarantees, etc........... yikes! Talk about rolling the dice! Good luck.

Don't get too serious. I am just saying you play with your car on your responsibility. It's not as dangerous as smuggling a kinder surprise egg to the U.S. I wrote so because I don't want to get blamed everything in unreasonable manner - which I often get and turned off messaging so.

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[a4android]

I attempted to PM you but it will not allow me to as I assume you have the functionality turned off here on the forum. Would you be willing to share the coding to make the Auto Hold state persistent? Without explanations on the long coding for this platform in VCDS I find the long coding to be a bear.

It's the same one as make the start and stop memorized. Will post later if someone else doesn't post. Outside now.

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[a4android]

I attempted to PM you but it will not allow me to as I assume you have the functionality turned off here on the forum. Would you be willing to share the coding to make the Auto Hold state persistent? Without explanations on the long coding for this platform in VCDS I find the long coding to be a bear.

- module 09-Cent. Elec.
- enter Security Code (20113)
- Adaptation on Channel 34:
subtract 4 to the value --> Start&Stop always disabled
add 32 to the value --> memorize last status (the Start & Stop status at engine startup will be the one at last engine shutdown)
- test & save

[Chiromikey]

Would anyone in their right mind really do this to their $70K Audi? Disclaimers, oops - I just noticed an error, no guarantees, etc........... yikes! Talk about rolling the dice! Good luck.

Do you ask this in every thread about modding? This is probably one of the least risk mods of all time...

[phaphaphooey]

- module 09-Cent. Elec.
- enter Security Code (20113)
- Adaptation on Channel 34:
subtract 4 to the value --> Start&Stop always disabled
add 32 to the value --> memorize last status (the Start & Stop status at engine startup will be the one at last engine shutdown)
- test & save

Thank you. I will be interested to see if it works on my car as it does not have stop-start.

[phaphaphooey]

- module 09-Cent. Elec.
- enter Security Code (20113)
- Adaptation on Channel 34:
subtract 4 to the value --> Start&Stop always disabled
add 32 to the value --> memorize last status (the Start & Stop status at engine startup will be the one at last engine shutdown)
- test & save

Also, do you know if this allows other settings to remain persistent in the car throughout power cycles? Specifically, I have been trying since I had the car to make the auto bright function on the headlights persistent so that you don't have to toggle it on every time you get in the car.

[a4android]

Also, do you know if this allows other settings to remain persistent in the car throughout power cycles? Specifically, I have been trying since I had the car to make the auto bright function on the headlights persistent so that you don't have to toggle it on every time you get in the car.

I will take a look when i have a chance, but i don't have headlight assist and don't know if it's allowed to memorized the last status. I think starting up with high beam on is generally prohibited.

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[phaphaphooey]

I will take a look when i have a chance, but i don't have headlight assist and don't know if it's allowed to memorized the last status. I think starting up with high beam on is generally prohibited.

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Thank you. Other cars makes allow this setting to be persistent so I would hope Audi would too. Since the high beams are only activated when no other cars are present it is allowed, at least around these parts.

[xxedwinxx]

So is it everything good? Working well with hillhold retro, I want to add the button and code everything but first want to make sure everything is cool. I’m in Canada I have 2013 S7 Do you think it is pre-wired?

[a4android]

yeah, no problem so far.
yeah, it's pre-wired.

[acamposac1]

Mine came in today. Just installed and coded as Daniel said and it works great. Will test it out on my commute tomorrow.

I never had a car with auto hold before, but I thought the rear brake lights are supposed to come on when auto hold is activated? Mine turns off as soon as I let off the pedal even though the car is holding the brake. Maybe further coding is needed? Otherwise I do not see a huge difference to using the e-brake when stopped if the rear brake lights don't stay on to prevent rear end collisions.

[Chiromikey]

Mine came in today. Just installed and coded as Daniel said and it works great. Will test it out on my commute tomorrow.

I never had a car with auto hold before, but I thought the rear brake lights are supposed to come on when auto hold is activated? Mine turns off as soon as I let off the pedal even though the car is holding the brake. Maybe further coding is needed? Otherwise I do not see a huge difference to using the e-brake when stopped if the rear brake lights don't stay on to prevent rear end collisions.

The brake lights should stay on so maybe you’re right about further coding. Also, the auto hold should remain active at each stop unlike the parking brake. I’m still waiting for mine that should have arrived already so I can’t give any actual info.

[acamposac1]

The brake lights should stay on so maybe you’re right about further coding. Also, the auto hold should remain active at each stop unlike the parking brake. I’m still waiting for mine that should have arrived already so I can’t give any actual info.

Autohold does remain active the entire trip after being turned on. Just no brake lights.

My coding came out to the same as Daniel's after making the changes.

[acamposac1]

After further research, it looks to be common on VW/Audis for auto hold to not keep the brake lights on. The logic behind this is the brake lights just signal a change in speed, and shouldn't be necessary when at a complete stop. This is common in Europe with a majority of manual cars which drivers do not hold the brake through the entire time while stopped at a light, stop sign, etc. It also is a courtesy to not blind drivers with super bright brake lights at night when stopped.

My main concern is that while its not your legal fault if you get rear ended because of this, I still do not want to get rear-ended....

[a4android]

Not sure if you are reliable if the rear light is not on its brightest.
The brightest brake lights indeed mean there is a change in speed.
Also, it's not like brake light goes completely off but in normal brightness when the auto hold is active.

I don't think less bright brake lights are 'go' sign for the vehicle behind you. All drivers bear the responsibility to keep the safety distance to avoid rear-end collision.
Indeed, you get fined if brake lights are turned off, but that's not the case for auto hold.

for example, in rural Canada, there are often junctions with extremely long traffic signal timing and some people put their car in parking(so the brake light goes less bright) while waiting and put the gear to drive in the green signal, and I never heard anyone gets pulled by cops for those conducts.

[acamposac1]

Not sure if you are reliable if the rear light is not on its brightest.
The brightest brake lights indeed mean there is a change in speed.
Also, it's not like brake light goes completely off but in normal brightness when the auto hold is active.

I don't think less bright brake lights are 'go' sign for the vehicle behind you. All drivers bear the responsibility to keep the safety distance to avoid rear-end collision.
Indeed, you get fined if brake lights are turned off, but that's not the case for auto hold.

for example, in rural Canada, there are often junctions with extremely long traffic signal timing and some people put their car in parking(so the brake light goes less bright) while waiting and put the gear to drive in the green signal, and I never heard anyone gets pulled by cops for those conducts.

Yes, I agree with you. I guess most people in the USA drive automatics and keep their foot on the brake when stopped, so they are used to seeing the bright brake lights if a vehicle is stopped (even for a long time).

This is not a big issue, though mercedes, bmw, honda, etc all keep their bright brake lights on with autohold, but audi/vw does not.

[Gravy Train]

Are there no other adaptations to set in the ABS module which might keep the brake lights activated?

I hate asking this but it's relevant to the install. Does anyone have tips, pointers or a procedure for lifting the shift boot and center console for access to swap out their switch? I'd like to avoid breaking plastics for this.