# Hold Assist retrofit coding issue



## Dai-P (Apr 11, 2017)

Hello and good morning all,
Apologies if this has been asked before but I’ve just retro-fitted hold assist to my 2017 TT s-tronic. New button behind the parking brake and wiring harness from kufatec. 
my auto elec guy checked the wiring several times and it’s all correct….but it just won’t code in. Tried VCDS and OBDeleven but each time it won’t accept coding changes. Has anyone come across this issue before?


----------



## xmab (Oct 31, 2021)

Hi, I recently carried out this upgrade to my 2016 TT, did you also purchase the obd dongle?


----------



## Dai-P (Apr 11, 2017)

I didn’t purchase the dongle with the cable as I already have OBDeleven and a mate has VCDS so thought either of them would code it.


----------



## xmab (Oct 31, 2021)

I am new to VCDS myself and am still exploring all the features this has to offer. Depending on where you are you are more than welcome to try my dongle.


----------



## Dai-P (Apr 11, 2017)

xmab said:


> I am new to VCDS myself and am still exploring all the features this has to offer. Depending on where you are you are more than welcome to try my dongle.


Did all work ok with the kufatec dongle? That’s a kind offer thank you. I’m in Warrington.


----------



## xmab (Oct 31, 2021)

I had no issues with the Kufatec dongle. I'm down south not far from Heathrow so a meet is not an option.

I'll have a look at the coding on mine as I'm there can't be too many differences between 16 and 17 models.

I'm no expert and maybe someone on the forum might know if an error in wiring would for some reason cause the coding to fail.


----------



## chelspeed (May 6, 2017)

Will cost about a quid to stick it in the post and another quid to return it. As a non-involved party that seems the obvious solution.


----------



## Dai-P (Apr 11, 2017)

xmab said:


> I had no issues with the Kufatec dongle. I'm down south not far from Heathrow so a meet is not an option.
> 
> I'll have a look at the coding on mine as I'm there can't be too many differences between 16 and 17 models.
> 
> I'm no expert and maybe someone on the forum might know if an error in wiring would for some reason cause the coding to fail.


That would be most appreciated thanks. I’d be more than happy to cover postage if you’d be prepared to send the dongle up to me for a couple of days. 😉


----------



## xmab (Oct 31, 2021)

That would have been my next move  PM me your address and i'll post this week.


----------



## Dai-P (Apr 11, 2017)

xmab said:


> That would have been my next move  PM me your address and i'll post this week.


PM’d you mate 😉


----------



## veesix (8 mo ago)

Dai-P said:


> PM’d you mate 😉


Did you end up with a successful outcome?


----------



## Jack Duckworth (Apr 1, 2021)

xmab said:


> I had no issues with the Kufatec dongle. I'm down south not far from Heathrow so a meet is not an option.
> 
> I'll have a look at the coding on mine as I'm there can't be too many differences between 16 and 17 models.
> 
> I'm no expert and maybe someone on the forum might know if an error in wiring would for some reason cause the coding to fail.


Hi xmab,

I wonder if you can help me.

I have also retrofitted the hold assist kit from Kufatec, but the dongle coding has not enabled the green (P). Everything else works as expected.

I can see that for A3 8V retrofits the coding changes three different bits in the 03 ABS module, but in my TT 8S only two bits have been changed by the Kufatec dongle in the ABS module.

You have said that you have VCDS (as I do), so would you be able to show me what your 03 ABS module coding was before and after the dongle coding. That would allow me to see what the dongle has changed in your retrofit, and hopefully identify the 3rd bit change which my dongle has not triggered.

All help much appreciated.

Jack


----------



## xmab (Oct 31, 2021)

Hi Jack,

Unfortunately coding was done before I purchesed VCDS so I would not have the original settings. I will look later today and come back with my settings.

Did you clear any fault codes which would have been thrown up if the battery was not disconnected? If I recall I also had this problem which was sorted by clearing any faults.


----------



## MGTS (8 mo ago)

Hi sorry to hijack the thread.

I am half way through installing this upgrade. I have installed the new button and have the wiring passed through the center console to under the glovebox.

however, I am stuck on how to get the wiring from the cabin in to the engine bay to connect to the ABS unit.

can anyone point me in the right direction of how to feed the wire through? I have searched the forums and the web but have drawn a blank.

thanks


----------



## xmab (Oct 31, 2021)

Hi, look to the right of the ABS module and look down, near the bottom you will see a rubber cover with what looks like a nipple about an inch long sticking out. Make a small cut with a pair of side cutters and push through a metal coat hanger or cable rod if you have a short one.

ABS unit you should see two Grey inserts plugs, these need to be removed to push in the wires on the loom. 

Not sure how far you have got with the module, and it is not obvious, but you need to push the red bar at the ends which only moves a couple of mm to release the pins.

I'll take some pics in the morning and post.


----------



## MGTS (8 mo ago)

Thank you that is really helpful. Will have a look under the bonnet in the morning


----------



## Jack Duckworth (Apr 1, 2021)

Hi xmab,

Sorry it has taken so long to come back to you, I’ve been away over the jubillee.

I took your suggestion to clear the fault codes, and after a bit more research found that Kufatec have a windows based dongle updating tool, so updated the dongle too and reinstalled.

Delighted to say that it worked and after many months now have a fully functional Green (P)!

As I did both together I cannot say which made the difference, but job done.

Thanks again for the suggestion.

Jack.


----------



## xmab (Oct 31, 2021)

👍 glad it all worked out well 😃


----------



## pcbbc (Sep 4, 2009)

So what got changed in the coding in the end?
xmab has kindly fitted a button and my wiring for me, but I’m stuck with the coding.
I‘ve managed to code the adaptation channel for HOLD ASIST to ACTIVE, but I’m stuck with the long coding.
Or is purchasing the dongle the only way?


----------



## pcbbc (Sep 4, 2009)

Answer for how to code this is here.


----------



## Jack Duckworth (Apr 1, 2021)

Sorry for late response,

For information only (use at your own risk), here is the ABS 03 module coding on my 16 plate TTS 8S Roadster before and after the successful hold assist retrofit.

Before 24 AA 60 8D 3A 9B 15 A9 40 94 08 66 C2 97 97 06 23 24 06 5C A8 02 10 43 E9 60 C4

After 24 AA 60 8D 3A 9B 15 A9 40 94 08 66 C2 97 97 *0E A3* 24 06 5C A8 02 10 43 E9 *70 C5*

Changes are in bold. You'll have to work out which bits and bytes have actually changed.

Hope this helps.

Jack


----------



## Evil Derboy (Jan 25, 2008)

I've fitted this yesterday using the Kufatec kit and coded using their dongle. I'm getting an error on the dash for "Parking Brake Fault" and "Hold Assist Unavailable". Double checked my install and cables are all correct. Checked with OBDeleven (I don't have VCDS) and it reports "AUTO HOLD - button lamp - Open circuit/short circuit to Ground (GND)". The button itself is permanently lit. When I press it, it stays lit, but I get two messages in the dash, the one about it only being available with the door closed and engine running and another following that saying "auto hold unavailable".

The parking brake works as normal and weirdly if I clear the fault with the engine running, seatbelt on etc. auto hold works and the Green P symbol illuminates but when I switch off and restart the fault comes back on again. 

Having checked against the long coding above, it hasn't been changed by the Kufatec dongle. The option for the green P isn't selected and the option for Autohold installed isn't selected either., so I'm guessing that the supplied dongle hasn't worked properly. Unfortunately, when I try to change any of these hex values, I get a "function not available" message in OBDeleven. I've tried various security access codes found online and developer mode but none of these work.

I've reached out to Kufatec for support but not sure how responsive they are. In the meantime, does anyone have any input on being able to make long coding changes in OBDeleven to the ABS controller? @Jack Duckworth what did you use?


----------



## pcbbc (Sep 4, 2009)

Please post your long coding. The coding error is due to not correctly mirroring the bytes as detailed here.

Byte 15 set bit 3
Byte 25 must also set bit 4 at same time (mirrored byte)

Byte 16 set bit 7
byte 26 must also set bit 0 at same time (mirrored byte)

If you don’t correctly mirror/reverse the values of the bits in the mirrored byte you will get a coding error.


----------



## Evil Derboy (Jan 25, 2008)

pcbbc said:


> Please post your long coding. The coding error is due to not correctly mirroring the bytes as detailed here.
> 
> Byte 15 set bit 3
> Byte 25 must also set bit 4 at same time (mirrored byte)
> ...


I read that post and copied the hex values for each byte but OBDeleven either stuck me in a security access code loop or said “function not available”. I didn’t understand what “mirrored bytes” meant but just copied the hex from @jack Duckworth’s post.

I’ll try again by changing the bits as you describe above.


----------



## Evil Derboy (Jan 25, 2008)

Ok so those bits that you’ve listed above are already set but the hex values are different due to various other bits in each byte being checked also.

24 AA 60 8D 1A 99 15 AA 40 96 08 6C C2 95 83 0E A2 24 06 58 A8 02 10 43 C1 70 45

Im still confused by the term “mirrored byte”. What does it mean exactly ad opposed to just setting a bit/byte? Does the combination of bits need to somehow match or be the opposite from Byte 15 and 16?I don’t understand this terminology in relation to the coding aspect.


----------



## pcbbc (Sep 4, 2009)

The mirror byte is just the reverse bit pattern of the other byte.
So 0x0E = 00001110b
becomes 01110000b = 0x70
etc

And you have also coded the adaptation?
IDE05263-AUTO HOLD functionality = activated

That should be all that is required. Otherwise I would suggest there is a wiring issue with the Kufatec kit.

I didn’t actually do my own wiring, I had another forum member kindly help me out. He did mention that there was another wire required on earlier vehicles, but mine was late enough to already have it. Perhaps try a PM to user xmab?

Edit:
Full details of the coding as best as I could make out here.

Note that a lot of the bytes are just derived from the car VIN, presumably in an attempt to detect modules and/or coding being transfer between vehicles and resulting in an invalid/unsafe ABS configuration on a vehicle with different equipment.

All the other bytes that contain coding info also have a mirror byte, presumably as either an integrity check against corruption or as a crude attempt to stop people recoding. Expect to see differences in these bytes with vehicle options such as manual/auto box, FWD/Quattro, etc.


----------



## b1ggles (6 mo ago)

EDIT... too slow


----------



## Evil Derboy (Jan 25, 2008)

pcbbc said:


> The mirror byte is just the reverse bit pattern of the other byte.
> So 0x0E = 00001110b
> becomes 01110000b = 0x70
> etc
> ...


Ah, I see. That makes sense. Thanks for clarifying. I originally changed the hex on the bytes in question and this would have done the same job. But OBDEleven wouldn’t accept the coding.

Adaption is done. 

There is an additional power cable in the wiring loom but on cars that already have a power cable present in the corresponding pin connector it’s not required (and mine does have this).

I’ve double checked the wiring and it’s 100% correct, so my suspicions are that the coding isn’t right or that the new switch is actually faulty (and given the functional behaviour, I’m leaning towards the latter). 

KUFATEC have come back today and asked for a scan and copy of the firmware on their dongle. At least they’ve come back to me quickly so let’s see what they say.

Thanks for your help! 👍🏻


----------



## Evil Derboy (Jan 25, 2008)

Just a quick update. I read a forum post somewhere on another Audi forum about people coding in Autohold without fitting the button and one guy mentioned that in order to not get errors you need to change an adaptation value in the ABS Module:1

Monitoring of functional lights
Indicator light in AUTO HOLD button
7


The default value has to be changed from 7 to 0 in that case (so as the lack of button doesn't create a fault). So going on my suspicion that the issue may be with the button itself, I've changed the value and it's cured the problem. The button is permanently lit when the ignition is on, regardless of whether Autohold is switched on or not, so it surely stands to reason that the button is indeed faulty?

What do you think? Does that seem like sound logic or am I missing something else?


----------



## pcbbc (Sep 4, 2009)

sorry, not enough experience to say. Somethings certainly not right, and I don’t think it’s coding. So I’d say either wiring or faulty switch.


----------



## b1ggles (6 mo ago)

Evil Derboy said:


> Just a quick update. I read a forum post somewhere on another Audi forum about people coding in Autohold without fitting the button and one guy mentioned that in order to not get errors you need to change an adaptation value in the ABS Module:1
> 
> Monitoring of functional lights
> Indicator light in AUTO HOLD button
> ...


There seems to be a load of reports on forums that Kufatec's instructions leave a lot to be desired and often include errors, pins reversed etc, don't know if that's the case here but might be worth double checking your connections against this how-to guide which also mentions less than perfect instructions...






Retrofit Hold Assist Audi TT (8S)


"Auto Hold" is often confused with "Hill Hold". Hill hold is standard on DSG TTs (not sure about manual cars) and holds the brake a bit on a hill to make is easier for you to set off. Auto-hold on the other hand, holds the brake for you when you take your foot off when stationary and still in...




www.deutschespeed.com





Might be as simple as the connections reversed at one end.

Do you have a link to the info about coding without the switch, would be interested to read their experiences.


----------



## Evil Derboy (Jan 25, 2008)

b1ggles said:


> There seems to be a load of reports on forums that Kufatec's instructions leave a lot to be desired and often include errors, pins reversed etc, don't know if that's the case here but might be worth double checking your connections against this how-to guide which also mentions less than perfect instructions...
> 
> 
> 
> ...


LOL! - Believe it or not, I wrote that guide last night. I'm Moonstone on that forum. I don't have that link. I saw it on a forum somewhere in relation to an RS3 but didn't save it.


----------



## b1ggles (6 mo ago)

Evil Derboy said:


> LOL! - Believe it or not, I wrote that guide last night. I'm Moonstone on that forum. I don't have that link. I saw it on a forum somewhere in relation to an RS3 but didn't save it.


Doh...nice job, particularly helpful to know how little trim you really need to remove to get it done. Haven't got a TT yet but everyone I like the look of seems to be missing Hold Assist even if they have expensive options like the matrix headlights. Got used to MB's version over the last 10 years so wouldn't want to lose it and to add insult to injury my lad's mid range 2017 Leon has it as standard and they're two tiers down in VAG.


----------



## Evil Derboy (Jan 25, 2008)

b1ggles said:


> Doh...nice job, particularly helpful to know how little trim you really need to remove to get it done. Haven't got a TT yet but everyone I like the look of seems to be missing Hold Assist even if they have expensive options like the matrix headlights. Got used to MB's version over the last 10 years so wouldn't want to lose it and to add insult to injury my lad's mid range 2017 Leon has it as standard and they're two tiers down in VAG.


I have Autohold in my other car and so I'm so used to being able to take my foot off the brake that I really missed it on the TT. It was onlky a £90 option when speccing a new car apparently so I'm baffled so many cars don't have it.


----------



## pcbbc (Sep 4, 2009)

I think it’s a marketing issue. If the benefits were better explained, it might be more popular.

I really didn’t see the need for it when building my spec, even at the discount price. But regretted it when i realised the VC displays the “place foot in brake to engage gear” every time you take the foot off the brake. Although I agree there are many other benefits also.


----------



## b1ggles (6 mo ago)

pcbbc said:


> I think it’s a marketing issue. If the benefits were better explained, it might be more popular.
> 
> I really didn’t see the need for it when building my spec, even at the discount price. But regretted it when i realised the VC displays the “place foot in brake to engage gear” every time you take the foot off the brake. Although I agree there are many other benefits also.


I'd agree with that but still ludicrous it isn't standard given it's the sort of feature that just is. Must cost them more to create multiple switches and wiring looms than just let everyone have it, like the way it went with leccy windows.


----------



## Evil Derboy (Jan 25, 2008)

So Kufatec have confirmed that the coding is correct and that my wiring is fine but they still don’t think it’s the switch! 😂


----------



## pcbbc (Sep 4, 2009)

I believe the wiring harness production is entirely automated, and as a result each harness can essentially be made to order. Once you (or your outsourced supplier) has invested in that tech it costs nothing to make custom harnesses per each individual vehicle spec. In fact it actually saves you money with the price of copper these days.

Also, if you include wiring for non-existant features there will be a redundant plug hanging at the end of the loom for some unconnected control module. So you’d have to secure that somehow or you’d have unwanted rattles.

Agree with the engineering of the separate switches though. Seems an expense you could do without and just install a common switch (as per MFSW which has NAV buttons regardless of figment). Mind you, as discussed, for some reason most people don’t seem to spec Hold Assist.


----------



## Jannerman (Nov 19, 2016)

@Evil Derboy : I bought the cable that runs between the switch and the ABS unit from Kufatec just after I bought they car new in late 2016. I picked up a secondhand switch on eBay and wired it it in as per their instructions which were correct for my vehicle. At the time, the Kufatec manual coding instructions were complete nonsense (they didn't even have 26 bytes!!! nor did they offer the"dongle" service for it then and anyway I doubt it would have worked either), plus their customer support were totally unable to assist and then completely abandoned me to my own devices. So you can understand why I'm not very trusting of Kufatec expertise!

It was over 2 years before I got info from a forum member that allowed me to finally get it working. You can't just copy the ABS module (03) coding from another car or even the complete byte values affected.

I just had to flip the individual bits as shown in bold below, leave all the other bits in those 4 bytes as per your original values:

byte 15
00000110
changed to
0000*1*110

byte 16
01010000
changed to
*1*1010000

byte 25
01100000
changed to
011*1*0000

byte 26
00001010
changed to
0000101*1*

You can see that bytes 25 & 26 mirror bytes 15 & 16 respectively both in the before and after values (as referred to earlier by @pcbbc)

P.S. Have you tested the continuity of the wiring between the switch and ABS module? not just that the wires are connected to the correct pins?


----------



## Evil Derboy (Jan 25, 2008)

Jannerman said:


> @Evil Derboy : I bought the cable that runs between the switch and the ABS unit from Kufatec just after I bought they car new in late 2016. I picked up a secondhand switch on eBay and wired it it in as per their instructions which were correct for my vehicle. At the time, the Kufatec manual coding instructions were complete nonsense (they didn't even have 26 bytes!!! nor did they offer the"dongle" service for it then and anyway I doubt it would have worked either), plus their customer support were totally unable to assist and then completely abandoned me to my own devices. So you can understand why I'm not very trusting of Kufatec expertise!
> 
> It was over 2 years before I got info from a forum member that allowed me to finally get it working. You can't just copy the ABS module (03) coding from another car or even the complete byte values affected.
> 
> ...


I've not tested the continuity of the wiring - is there a way to do that without having to try and connect my multimeter from the engine bay to the cabin to do a resistance check? 

The button and the autohold function are fully functional as expected but the light on the button stays on permanently when the ignition is live. I'll try changing the individual bits as when changed the HEX for the byte, it didn't accept it.

What diagnostics mode did you use and what security password did you enter? (I'm using OBDeleven).


----------



## b1ggles (6 mo ago)

Evil Derboy said:


> I've not tested the continuity of the wiring - is there a way to do that without having to try and connect my multimeter from the engine bay to the cabin to do a resistance check?
> 
> The button and the autohold function are fully functional as expected but the light on the button stays on permanently when the ignition is live. I'll try changing the individual bits as when changed the HEX for the byte, it didn't accept it.
> 
> What diagnostics mode did you use and what security password did you enter? (I'm using OBDeleven).


Probably a ball ache to get to the switch end again but simplest would be short the two pins together with a paper clip at one end of the cable and check the continuity between the two pins at the other with your meter. 

From that error message you posted elsewhere it does sound more like the switch itself but have you got a wiring diagram to show how the led in the switch is powered? Could be existing but previously unused wiring causing the issue.


----------



## Evil Derboy (Jan 25, 2008)

b1ggles said:


> Probably a ball ache to get to the switch end again but simplest would be short the two pins together with a paper clip at one end of the cable and check the continuity between the two pins at the other with your meter.
> 
> From that error message you posted elsewhere it does sound more like the switch itself but have you got a wiring diagram to show how the led in the switch is powered? Could be existing but previously unused wiring causing the issue.


That's a great idea with the paperclip!

I don't have a wiring diagram but should be able to find one online. I'm going totry @Jannerman's bit combos first then I'll check the wiring.


----------



## Jannerman (Nov 19, 2016)

Hi @Evil Derboy, I used a different coding device to you (although I also have OBD11 as well, I didn't use it for this). I used VCP (VAG Can Pro), and my notes say I was in "Engineering mode" with SA (Security Access) code 7140.

Initially, I had issues getting the module to accept the coding because I wasn't setting the mirrored bytes at the same time (15 with 25) & (16 with 26), I "THINK" it will accept saving the each mirrored pair separately, but I reckon it's best to just set all 4 bytes at the same time.

P.S. Look out for a PM regarding Wiring Diagram


----------



## Evil Derboy (Jan 25, 2008)

Fantastic @Jannerman thanks for this. Got your PM as well. 👍🏻


----------



## Evil Derboy (Jan 25, 2008)

Checked the coding. The Kufatec dongle hasn't mirrored Byte 16 with Byte 26 and both of those bytes are different from the coding found online. When I go into the long coding helper, the option for the Green (P) is NOT ACTIVE. When I try to change the values for Byte 16 or Byte 26 it won't allow the coding. When I mirror Byte 25 with Byte 15 it does allow that.

Apart from the fact that the coding seems to fly in the face of what's been described here, the functionality does work, apart from the fault with the button lamp, so I'm back to suspecting a faulty button or an issue with the wiring loom. As described, everything is in the right place, but thanks to @Jannerman's wiring diagram, I've spotted that the ground wire for the lamp is linked to Earth Point 1 (687) on the centre tunnel. Does anyone know where this is? Seems too much of a coincidence that I removed and reinstalled the entire centre console recently.


----------



## Evil Derboy (Jan 25, 2008)

Well I think I've cracked it! Thanks to @Jannerman very kindly sending me the wiring diagram. I found the diagram for the ABS connector and although KUFATEC support said my wiring was correct based on my pics. It looks like i've put the wire for Pin 32 into Pin 33 on the connector!


----------



## Jannerman (Nov 19, 2016)

^ Good to hear you're making progress  If you still need it, the earth point information is in the wiring diagram, page 801/2 item 687


----------



## Evil Derboy (Jan 25, 2008)

Moved the pin in the connector 1 step to the right and problem solved. What a muppet! Least it’s an easy fix!


----------



## b1ggles (6 mo ago)

Evil Derboy said:


> Moved the pin in the connector 1 step to the right and problem solved. What a muppet! Least it’s an easy fix!


Well done, I don't need to consider crossing any off the list that come without it now


----------

