Sample long coding and clarification for 2017 Jetta before purchase of HEX-V2

   #1  

gokarty

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Hi,

I'm looking to buy the HEX-V2 for my 2017 NAR VW Jetta SEL (MK 6 Face Lift)

But before purchasing is there any way of getting sample screenshots of how many bits are actually labeled in the long coding helper along with which adaptation channels I can modify? The reason I ask is because I have had a bad experience in the past with another device so wanted to be sure that I can actually use the cable and not have a bunch of unlabeled bits where I can't modify anything with confidence

Also, could someone guide me if the following is actually possible:
I have to often go through a security checkpoint and the DRLs on the 2017 Jetta are causing problems for me since Im required to turn them off but I can't turn them off through MFD like the GLI owners since my BCM is PQ25

I read that I can bend the TFL pin and/or use VCDS to turn off DRL but I like the DRL and it's safety features so I was wondering if it's possible to only have them off when the light switch is in 0

Thank you very much! :)

Kind Regards,
gokarty
 
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dnoermann

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Whell, in generall the Labeling of LongCoding Bits in VCDS must be seen as good guess of the functionality ...
Because it is only found by reverse trying out and rengeneering the functionality ...
You have to ask a bit more precise, on which control unit you are interested ?
A normal car does have 20 ECU´s mostly every one does have LongConding ...
 
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Uwe

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Without knowing exactly which BCM your car has, no, that's not possible. I mean we could guess, but then if you had a different one, we'd be wrong anyway.

And even if we did know exactly what BCM you had, I'd be reluctant to post it all, because if it showed exactly what bits you needed to tweak, then you could just use the other device to do it and wouldn't need to buy VCDS at all, right? ;)

I'm not that familiar with the Mk.6 facelift Jetta. I suspect the way DRLs work on those might be buried in the magical mystery tour hidden behind Byte 18.

Does your headlight switch have an "Auto" position?

Do your DRLs not turn off if you pull up on the handbrake just a little bit?

-Uwe-
 
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gokarty

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Sorry if I wasn't clear enough, my bad

The BCM is the PQ25

Yes, I have an AUTO switch with the RLS (Rain Light Sensor) installed

And the Control Unit I'm interested in is the Central Electrics

The 2017 Jetta uses an LED strip built into the headlight housing which is very bright when DRL is active but dims when headlights turn on kind of a copy of Audi style headlights. Yes, the DRLs turn off when i lift the handbrake but I have to go through multiple checkpoints and keeping my hand on the hand brake and slightly pulling up was my first choice but it has caused considerable problems with the security personnel
 
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gokarty

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Also Uwe, I understand why you are reluctant to post the bits and the labels but maybe you can post a screenshot of the long coding helper available and blur out the text so that the screenshot itself is useless but atleast it could give me an idea that the bits do actually have labels? I am not trying to fool or cheat Ross Tech in any way, just genuinely interested in buying the cable but wanted to not have a repeat episode by buying something that didn't help me
Hope you understand

Thanks for your help!
 
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Uwe

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Not all BCM PQ25 modules are the same. They come in several variants... Got a VW part number? Then I could at least look for a scan that includes this part number.

-Uwe-
 
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gokarty

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Not all BCM PQ25 modules are the same. They come in several variants... Got a VW part number? Then I could at least look for a scan that includes this part number.

-Uwe-
Sure, the BCM is PQ25 Max3

Hardware Number : 7E0937190
Hardware Version : H81
Serial Number : 88003324160043
 
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gokarty

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@dnoermann
Appreciate the info, thank you, however I just wanted to get a clear idea for the latest VCDS version since I figure that there may have been more bits discovered/labelled in the past few years :)
 
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gokarty

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Hi Uwe, any luck?

Meanwhile I have an interesting observation to point out. Last night I tried removing every single pin in the headlight switch individually but not a single PIN controlled the DRLs. However, when I start my car without the headlight switch installed, the headlights(low-beam) turn on, even though there is no switch!

These findings are encouraging and discouraging since they give me hope that the BCM is controlling the DRLs so VCDS might actually be able to accomplish what I would like however it also sucks that I cannot just wire in a switch to the "TFL" pin and have DRL on demand literally like a light switch

Do you think purchasing documentation/service manual from erWin would help you or me?
 
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Uwe

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Yes, the DRL behavior is definitely controlled by the BCM.

However, I do not think you can achieve what you desire with coding. I believe what you are looking to do would require modification of the EEPROM data in the BCM, which VCDS cannot do. Hence if this is the main thing you want VCDS for, I recommend against purchasing it.

No, I do not think erWin would be helpful in any way.

-Uwe-
 
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gokarty

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Yes, the DRL behavior is definitely controlled by the BCM.

However, I do not think you can achieve what you desire with coding. I believe what you are looking to do would require modification of the EEPROM data in the BCM, which VCDS cannot do. Hence if this is the main thing you want VCDS for, I recommend against purchasing it.

No, I do not think erWin would be helpful in any way.

-Uwe-
Thanks for your honest help! It is disheartening about the DRLs however looking at the wealth of resources and features offered by VCDS and the amazing help given by the community, I think I'm gonna go ahead and and order the HEX-V2 by today, thanks for all your help and looking forward to becoming a member of the VCDS community

Kind Regards,
gokarty
 
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DV52

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Meanwhile I have an interesting observation to point out. Last night I tried removing every single pin in the headlight switch individually but not a single PIN controlled the DRLs. However, when I start my car without the headlight switch installed, the headlights(low-beam) turn on, even though there is no switch!
gokarty: hmm........ you certainly are somewhat of a "forum butterfly" (no offense intended) -I didn't know in which thread to post my reply to your repeated observation !!;)

So - I wanted to suggest a reason why (perhaps) your observation above occurred and to do so, I've borrowed (in the picture below) a section of the WD from a mk6 Golf (because it appears to be closest in build platform for your Jetta). However, I emphasis from the outset that my picture is NOT from the 2017 Jetta WD - I don't have that particular WD.



In the picture, I've shown the connections between the BCM and the rotary light switch and in particular how VW indicate the internal wiring for the LDS.

Not sure how familiar you are with VW WD s, but they tend to use DIN 72552 standards which define "Terminal numbers" for the various electrical functions in a vehicle. As an example of how to read the WD (and I apologize in advance if you already know this stuff) take the designation for the pin on the extreme LHS of my picture on the LDS (called "E1") which is T10h /4 15a.

For this pin on the LDS: T10 means that this pin is on a 10 x pin connector - 4 means that this is pin#4 - 15 means that this pin has "Terminal 15" function as defined in DIN 72552. Note that I have included on my picture the DIN 72552 functions for ease of reading.

So- for the purpose of the observation in your quote, notice how the ganged, multi-pole switch-bar in E1 applies a T30 voltage to (nearly all) the BCM pins. Importantly for your observation, notice how the multi-pole switch does the opposite for the TFL pin (the DRL function): this pin on E1 has +12V applied in the normal state (which I read to be the normal DRL-ON state with the dial set in the 0 position).

If you are following my explanation, I hope that you will see that when you removed the 10 x pins at the rear of the LDS - you disconnected the T30 voltage to the TFL pin on E1 and in effect this generated a DRL OFF signal to the BCM.

Now, normally - because of the ganged nature of the multi-pole switch in E1, the DRL OFF signal would be interpreted differently by the BCM depending on which of the other pins on the BCM received a T30 voltage (i.e. which light function was selected by the driver). In this case however - none of the other pins on the BCM received a T30 voltage (because the other pins were un-plugged)- so the BCM simply interpreted the DRL OFF command as meaning turn-on the night-time lamps.


QED

Don

PS:I can hear you saying to yourself "Bingo -if the Jetta has the same set-up, that's the answer to my SPST switch problem: I simply need to disconnect pin #9 on the LDS". However, as you have observed, this switches-on the low-beams and Parking lights. And, as I suspect happened when you disconnected the 10 x pins, the BCM also said "WTF is happening here? Where is the missing T30 voltage on my other pins telling me which night time lights to turn-on?" - which was translated more politely as a DTC on the CAN network as a "implausible state error"!

So, I suspect that Uwe's conclusion above is correct (it normally always is correct), but with the exception that the WD is useful for the sole purpose of demonstrating why a SPST switch won't work
 
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   #14  

gokarty

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gokarty: hmm........ you certainly are somewhat of a "forum butterfly" (no offense intended) -I didn't know in which thread to post my reply to your repeated observation !!;)

So - I wanted to suggest a reason why (perhaps) your observation above occurred and to do so, I've borrowed (in the picture below) a section of the WD from a mk6 Golf (because it appears to be closest in build platform for your Jetta). However, I emphasis from the outset that my picture is NOT from the 2017 Jetta WD - I don't have that particular WD.



In the picture, I've shown the connections between the BCM and the rotary light switch and in particular how VW indicate the internal wiring for the LDS.

Not sure how familiar you are with VW WD s, but they tend to use DIN 72552 standards which define "Terminal numbers" for the various electrical functions in a vehicle. As an example of how to read the WD (and I apologize in advance if you already know this stuff) take the designation for the pin on the extreme LHS of my picture on the LDS (called "E1") which is T10h /4 15a.

For this pin on the LDS: T10 means that this pin is on a 10 x pin connector - 4 means that this is pin#4 - 15 means that this pin has "Terminal 15" function as defined in DIN 72552. Note that I have included on my picture the DIN 72552 functions for ease of reading.

So- for the purpose of the observation in your quote, notice how the ganged, multi-pole switch-bar in E1 applies a T30 voltage to (nearly all) the BCM pins. Importantly for your observation, notice how the multi-pole switch does the opposite for the TFL pin (the DRL function): this pin on E1 has +12V applied in the normal state (which I read to be the normal DRL-ON state with the dial set in the 0 position).

If you are following my explanation, I hope that you will see that when you removed the 10 x pins at the rear of the LDS - you disconnected the T30 voltage to the TFL pin on E1 and in effect this generated a DRL OFF signal to the BCM.

Now, normally - because of the ganged nature of the multi-pole switch in E1, the DRL OFF signal would be interpreted differently by the BCM depending on which of the other pins on the BCM received a T30 voltage (i.e. which light function was selected by the driver). In this case however - none of the other pins on the BCM received a T30 voltage (because the other pins were un-plugged)- so the BCM simply interpreted the DRL OFF command as meaning turn-on the night-time lamps.


QED

Don

PS:I can hear you saying to yourself "Bingo -if the Jetta has the same set-up, that's the answer to my SPST switch problem: I simply need to disconnect pin #9 on the LDS". However, as you have observed, this switches-on the low-beams and Parking lights. And, as I suspect happened when you disconnected the 10 x pins, the BCM also said "WTF is happening here? Where is the missing T30 voltage on my other pins telling me which night time lights to turn-on?" - which was translated more politely as a DTC on the CAN network as a "implausible state error"!

So, I suspect that Uwe's conclusion above is correct (it normally always is correct), but with the exception that the WD is useful for the sole purpose of demonstrating why a SPST switch won't work
Hi Don,

thanks for your input!

Yes that makes sense! After going through the wiring diagrams and the fuse assignments myself, I figured that there is no easy way of wiring an SPST / DPDT

So, I guess I'm going to have to take the longer route of wiring a switch at the BCM output, however can you help me with a few questions that might sound dumb:

1) According to the Wiring Diagram, I need to tap/disconnect a wire connected to pin 3 on a T73b connector, watching the Ross Tech videos (really helpful btw!) I know that it's a 73-pin connector connected to the BCM, but since it also has a "b" that means that there already are other 73-pin connectors used in the diagram, how do I locate the correct connector and pin 3 on the BCM?

2) After locating the connector, how do you open it? Is it possible? I figured rather than cutting wires, it's safer (and easier to reverse) to remove the wire from the connector and make my own circuit with a SPST that plugs in

Also, here is the wiring diagram for your reference : https://imgur.com/a/SHcHcBb

Mu understanding is I need to wire a switch inline with the blue/white wire that runs to "L174" Left Daytime Running Bulb
 
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DV52

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Hi Don,

thanks for your input!

Yes that makes sense! After going through the wiring diagrams and the fuse assignments myself, I figured that there is no easy way of wiring an SPST / DPDT

So, I guess I'm going to have to take the longer route of wiring a switch at the BCM output, however can you help me with a few questions that might sound dumb:

1) According to the Wiring Diagram, I need to tap/disconnect a wire connected to pin 3 on a T73b connector, watching the Ross Tech videos (really helpful btw!) I know that it's a 73-pin connector connected to the BCM, but since it also has a "b" that means that there already are other 73-pin connectors used in the diagram, how do I locate the correct connector and pin 3 on the BCM?

2) After locating the connector, how do you open it? Is it possible? I figured rather than cutting wires, it's safer (and easier to reverse) to remove the wire from the connector and make my own circuit with a SPST that plugs in

Also, here is the wiring diagram for your reference : https://imgur.com/a/SHcHcBb

Mu understanding is I need to wire a switch inline with the blue/white wire that runs to "L174" Left Daytime Running Bulb
GoKarty: hm......... I'm not entirely sure that you wiring diagram is correct for your specific car - but first, let me answer your questions:

Question 1): You are indeed correct in assuming that "there already are other 73-pin connectors". In fact, the "other 73-pin connector" is actually on the same PQ25 BCM. When a BCM pin on a WD has the alpha "a", "b" (or "c") - it is referring to the connector that has the same alpha stamped in capital letters on the BCM housing. So T73b /3 means pin #3 on the 73 x pin connector on socket B. Here's how to find socket B on a PQ25 BCM:



If you look again at your WD, you will see mention of T73a - this is socket A in the picture above

Question 2) Each of the sockets on the BCM normally have their -own retaining catches to ensure that the connections don't shake loose. It's normally just a matter of releasing the catch, then forcing one end of the socket slightly inwards - but I suggest that you get hold of the Electrical systems document for your Jetta which will describe the location of the BCM and how to release the catch - if you want.

However - a few other matters that you might want to consider before proceeding:
  1. As I prefaced in my opening remarks, your wiring diagram seems a tad strange because you have mentioned in a previous post that the DRLs on your car are a LED string. Worryingly however, the WD shows a headlight assembly that consists entirely of incandescent lamps. I've no doubt that the WD is for a Jetta - but I suspect that the specific wiring arrangement in your picture isn't the correct headlight option for your car. Whilst it's highly likely that the same BCM pin is used for the DRL on your fitting - I always prefer to eyeball the correct WD as positive confirmation before cutting any wires on a car
  2. You might want to think further about cutting the BCM output pin to the DRLs and using a separate switch to turn ON/OFF the lamps: the PQ25 is a sophisticated device which contains it's own fault monitoring circuits. If the BCM senses that there is no electrical current flow when it energizes the DRL output pin (because your new switch has open-circuited the wire to the LED strips) - it will generate a DTC with an accompanying message on the dash indicating a faulty fitting.
  3. If you proceed, you might think about NOT doing any splicing/cutting at the BCM socket: it's cram packed with other wires and generally it's not a good place to make modifications unless absolutely necessary (IMHO) : it's far easier I suspect to make connections in the engine bay loom where access is more straight-forward (if you want to proceed)

Don
 
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gokarty

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GoKarty: hm......... I'm not entirely sure that you wiring diagram is correct for your specific car - but first, let me answer your questions:

[...]
Don,

Thank you for the clarifications and help, I'm going to try and find a wiring diagram with the LED strip accounted for, if that's not possible, I'm gonna try using a DMM at the headlight connector to figure out which wire controls the DRLs

Thanks for your help!
 
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   #17  

DV52

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gokarty: Please understand that while I'm more than happy (ecstatic - in fact;)) to answer your questions, I'm certainly NOT recommending that you proceed in your endeavor (for the reasons I've stated).

Ultimately however, I assume that you are a sane, sentient being - with the mental capacity to make your own decisions!! :)

Good luck and please keep us (me, really) informed of progress !!

Don
 
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gokarty

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gokarty: Please understand that while I'm more than happy (ecstatic - in fact;)) to answer your questions, I'm certainly NOT recommending that you proceed in your endeavor (for the reasons I've stated).

Ultimately however, I assume that you are a sane, sentient being - with the mental capacity to make your own decisions!! :)

Good luck and please keep us (me, really) informed of progress !!

Don
Don, thanks for your input, will keep you posted
As for now, I'm not doing anything until I have done some more research and can be more confident in my abilities!

Thanks and Regards,
gokarty
 
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