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Post by CallumW on May 15, 2021 23:51:58 GMT
Hi I have a real bugbear with stopping at lights and the car in front dazzling me with their braking lights instead of using their handbrake.
I recently upgraded from a '03 Golf Tdi to an '18 S3 and I noticed that when the Hill Hold is activated that the brakes lights stay on even although my foot is off the pedals. It's a totally pointless feature The only way I found to stop it is to manually apply the proper parking brake which immediately kills the brake lights.
The problem there is that the car squats a bit before pulling away due to the delay in disengaging the parking brake. I'm sure that's not doing the transmission or brakes any favours.
My question is if there's a away to stop the brake lights illuminating when the Hill Hold Assist activates?
Ta CW
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Post by dv52 (Australia) on May 16, 2021 3:17:23 GMT
Callum: Although it would be a delight to debate the part of your post that says "Its a totally pointless feature", I nevertheless applaud you for asking a most excellent question!! I have built a "virtual" MQB platform vehicle as a test-bench (see below) and it has been a very useful tool in understanding how the boffins @ Audi/VW have designed particular elements in the car: Now notwithstanding that my test bench does not have a brake module (happy to be given a hex03 module if anyone has a spare), it does simulate the Brake lights via the panel in the lower part of the picture.
So- what I've found over the time that I've played with my test bench is that Brake lights on MQB platform vehicles like your S3 are special in that they use 2 x separate processes for lamp illumination as follows:
route 1: there appears to be a direct link between the functioning of the Engine-Control-Module (ECU) and the brake light which is probably an in-built safety feature. I've not discovered the exact nature of his link - but it can't be broken (at least not by any method that I have tried). route 2: there appears to be a different path to illuminate the brake light that is used by various "driver-assist" systems -like Adaptive Cruise Control. When ACC decelerates the car speed because the car in front has slowed down, it sometimes applies the brakes and as a consequence the brake light illuminates. I call this the "CAN" path because the brake light switch-on signal must be passed between a number of modules over the car's CAN network (I think)
AFAIK, the brake lights are unique in this respect - no other of the 35 x exterior lights on the car have these 2 x switch-on/off paths
Alas, I don't have a definitive answer to your question, but I suspect that you won't find a straight-forward coding solution because I believe that the factory-set safety locks for the brake lights (justified, or otherwise with the inclusion of Hill-Hold) will be binding. And even if a way of breaking the factory programming locks is found, I very much doubt that OBD11 can be used in the solution.
This said, you might try an experiment: As I have noted above, route 1 is sacrosanct and it's unbreakable IMO. However, it is possible to defeat route 2.
I'm not sure if you are aware of "Leuchte-sets" but each of the exterior lamps on the car is operated by an individual Leuchte-set. A Leuchte-set consists of 19 x adaptation channels that live in the central electrics module, and each Leuchte-set has a name commencing with the word "Leuchte".
The particular Leuchte-set for the left-side brake light on most (all?) MQB platform cars is Leuchte20BR LA71. Within this Leuchte-set is the adaptation channel Lichtfunktion A 20 and the factory value of this channel is Bremslicht (which is German for "Brake-Light"). This is the software switch that enables route 2 and it could be that changing this value to nicht aktiv (i.e. not active) might be the answer to your question (I'm guessing, of course).
BUT (and there is always a "but") if my suggestion above does work in not switching-on the brake-lights when hill hold is active, it will also stop other assist system from doing the same (like ACC). Is this acceptable?
Plus you should confirm with above adaptation channel setting changed that a normal press of the brake pedal still illuminates the brake-light (I believe that it will not affect the normal brake-light operation)
Don
PS: If my suggestion above is successful/acceptable, you will need to also change the Leuchte-set for the right-side brake light - which is Leuchte21BR RC8
PPS: the security code for changes is 31347
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Post by CallumW on May 17, 2021 10:48:45 GMT
Hi Don Wow ... that's quite a setup you have there. That must have taken a while and a fair bit of effort to put that together. I was aware of the Leuchte-sets from playing about with the app. On YouTube (v=O6-FWDX0jVY) I saw a Canadian guy use them to change the indicator method on his GolfR to a way that he liked them, so I've seen what they can do and how fiddly they can be, but didn't delve into them at all as I don't know what I'd be doing ... it's all German to me I totally get your point on the 2 routes to activating the brakes. Makes sense that brake pedal activation is unbreakable as it should be, but that the secondary activation circuit may be controllable to an extent. It was a very good point about ACC where the light may activate if the braking force increases beyond a set value. I hadn't thought about that aspect. Presumably a similar scenario if emergency/collision prevention braking is one of the subsystems. I've seen TV adverts showing anti-collision on some cars and the rear lights usually strobe to indicate heavy braking to any following traffic. The way I see the Hill Hold Assist though is that it's a soft version of the parking brake, so there's no need for brake lights. If I'm stationary and someone was approaching, depending on their speed I may touch the brake pedal for a second just to make sure they're aware of me there. I don't have ACC on my car, so I'll do a fresh backup of my central electrics later and then have a go at your suggestion and feedback the result. CW
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Post by CallumW on May 18, 2021 10:34:49 GMT
___________________________________________________________________________ Addendum: I went down last night to try it out, but the app doesn't seem to be working atm. Looks like a server issue to which the app can't connect to retrieve my details.
I'm trying again atm in my home, but the app still can't connect. Hopefully they'll sort it out soon.
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Post by CallumW on May 18, 2021 20:13:42 GMT
Ok. Figured out what was wrong with the app and why it wouldn't connect. Turns out it needed updating from Google PlayStore. I followed your suggestion for the lights, but unfortunately it said that the Adaption for Lichtfunktion A 20 was already not active. To make double sure I was in the car with parking brake off, AutoHold on, Hill Hold assist active and the brake lights were on (feet off the pedals). I guess this makes sense as I don't have ACC or any other diver assistance features other than parking sensors and camera, so it would already be disabled. Unless it's Lichtfunktion E 20 that does the magic? I've attached a picture of the available options for the car within Leuchte20BR LA71 so you can see what was active and not.
I'm not sure why that would be different, but here are my subsystems in case that's useful?
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Post by CallumW on May 18, 2021 20:50:36 GMT
Looking a bit more into the options and I see there are 3 Leuchte[nn]BR [WXYZ] items in my list. Leuchte20BR LA71 Leuchte21BR RC8 Leuchte22BR MA57Below are the options available and I see the Leuchte22BR MA57 has Lichtfunktion A 22 as BremslichtI'm now wondering is the 3rd is a spoiler brake light and this is the only one that activates when Hill Hold is active. Not sure and it's hard to check when I'm on my own in the car. Might need to reverse to a shop window and have a wee investigate.
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Post by dv52 (Australia) on May 18, 2021 23:20:00 GMT
hmm....... lets deal with the "ancillary" matters in your response first:
screenshot 2
looks normal - tells me that the car is equipped with (in order shown) : - Front windscreen washer
- Rain Light Humidity sensor (attached to the windscreen)
- Rotary Light Switch
- Anti-theft Alarm sensor
- Anti-theft Siren
- Sun-roof
screenshot 3 looks normal - as to whether it's a "spoiler" - you should be able to provide your own answer to this question. I would suspect that if the 2 x outer brake-lights operate with Hill-hold, the 3rd Brake light will do the same - but you can verify
Screenshot 1 & 4 Not as I expected - but the two Leuchte-sets are not unexpected in the vast range of Leuchte-programming variations in different versions of A3/R3/RS3 8V's across different world markets
Leuchte20BR LA71= Brake light on left-side tail-light cluster
Leuchte21BR RC8 = Brake light on right-side tail-light cluster
I assumed the Bremslicht command would be on Lichtfunktion A (it usually is), but it happens to be on Lichtfunktion E on your car - no big deal!!
Just proceed as I suggested but change Lichtfunktion E 20 in the first instance - if the experiment works, change Lichtfunktion E 21 & Lichtfunktion A 22
Don
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Post by CallumW on May 19, 2021 0:01:00 GMT
Yes! That is it. You are amazing I changed the following to nicht aktivLeuchte20BR LA71 - Lichtfunktion E 20 Leuchte21BR RC8 - Lichtfunktion E 21I didn't need to change the Leuchte22BR MA57 Adaption, so left that as-is. Tested to make sure regular brake lights also come on with the pedal with and without Hill Hold and Parking Brake it all works perfectly Thank you CW
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Post by dv52 (Australia) on May 19, 2021 0:14:35 GMT
Well done!! We have both learned something as a result of your experimentation (thank you) -and another happy OBD11 user is always a good thing!!
A final note as a concluding suggestion : We haven't discussed this, but a matter that always is pertinent to these types of tweaks is does the change affect what we Aussies call the car's "road-worthiness"? Said another way - is the car still road-legal with the modification implemented? I don't know this answer and I rely entirely on your judgement/research-findings in this regard.
For clarity- the liability that I take in providing advice on this forum is EXACTLY equal to the fiscal reward that I receive (which ain't much!!)
Don
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Post by CallumW on Jun 1, 2021 2:20:48 GMT
Addendum I did have to change the Leuchte22BR MA57 Adaption : Lichtfunktion A 22 from Bremslicht to Nicht AktivIt was only tonight I realised it was still activating as I saw the 3M tape on traffic cones light up at a set of traffic lights. Checked in a shop front window and right enough, the top mini-brake light still came on. Making the change above disabled it
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bmcjp
New Member
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Post by bmcjp on Aug 27, 2022 11:33:39 GMT
Just to revive an old thread, wondering if you would have any information on this with an 8U Q3, under central electronics there are no options for brake lights as described in this thread. Have added Auto Hold feature, enabled with in coding under parking brake successfully however, when enabled and stopped, brake lights do not stay on and auto start stop feature does not operate unless brake pedal pressed. Any assistance would be appreciated. Thank you Well done!! We have both learned something as a result of your experimentation (thank you) -and another happy OBD11 user is always a good thing!!
A final note as a concluding suggestion : We haven't discussed this, but a matter that always is pertinent to these types of tweaks is does the change affect what we Aussies call the car's "road-worthiness"? Said another way - is the car still road-legal with the modification implemented? I don't know this answer and I rely entirely on your judgement/research-findings in this regard.
For clarity- the liability that I take in providing advice on this forum is EXACTLY equal to the fiscal reward that I receive (which ain't much!!)
Don
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Post by dv52 (Australia) on Aug 27, 2022 21:11:29 GMT
bmcjp: Hi "AU Q3"? Hmm...... this car was built on a the Volkswagen Group A (PQ46) platform - well before the introduction of MQB platform cars which are the subject of this part of the forum. Audi Q3 was transformed to MQB platform in 2018 (the F3 model) So - bottom line, your Q3 probably doesn't have the newer type UDS/ODX modules that are used on MQB platform cars and I very much doubt that it uses Leuchte-sets. Maybe try the Q3 forum Don
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