Assistance Needed for Programming BCM for LED Fog Lights on VW Golf MK7 (2014 TDI to

[DV52]

Alek: Bummer!!!

Alas, I don't understand any of your words in your response above that starts "Ok, so I am isolating errors specific to LED errors. These two replace this from long coding to channel coding..........."

I reaching the end of my suggestions - I ask once more:

Maybe post-up a BCM admap (as a URL link - don't dump the data directly in your post) so we can see how this puppy is programmed!!

If you aren't familiar with the process of creating a BCM admap with VCDS, see my instructions below:

From the VCDS opening screen below, select Applications



From Applications screen, select Controller Channel Map



In the Maps dialogue box, set-up the variables EXACTLY as shown below (take care with this step - check the boxes correctly):



Press the Go button and wait for the magic to finish!

Once the process is complete, look in the sub directory C:\Ross-Tech\VCDS\Logs on your laptop and you should find a new file starting with the name admap-09-5Q0-937-084-AC.......CSV.

Now, because this forum won't accept a .CSV file, you will need to post-up the admap to a third-party hosting site (like dropbox, or any of the lots of other sites). Then include a URL-link to the file in a new post here

Don

[ak77]

Hi Don,

Here is the link where to download the file. Also included the text file format along the VCDs export CSV
Al
Unique Download Link | WeTransfer


1. Update Fog Light Adaptation Channels
Left Fog Light (Leuchte12NL LB45)
Current Settings:

Lasttyp 12: 6 - LED Lichtmodul ✅

Dimmwert AB 12: 127 ✅

Fehlerort mittleres Byte DTC-DFCC 12: 00 (Error reporting disabled).

Missing: Kaltüberwachung aktiv (Cold Monitoring Active).


Right Fog Light (Leuchte13NL RB5)
Current Settings:

Lasttyp 13: 6 - LED Lichtmodul ✅

Dimmwert AB 13: 127 ✅

Fehlerort mittleres Byte DTC-DFCC 13: 00 (Error reporting disabled).

Missing: Kaltüberwachung aktiv (Cold Monitoring Active).



Thanks mate

Al

[DV52]

Al: hmm.......... that's a mighty odd BCM admap!

Your BCM has P/N & S/N 5QO-937-084-AC. The nearest BCM in my database is an Aussie 5Q0-937-084-AE. I've created a BCM compare spreadsheet for the 2 x modules that you will find HERE

This is how the spreadsheet works:
Worksheet "BCM compare AC and AE"

1. Contains a list of ALL channels and values in your BCM compared to the AE BCM - if the AE BCM has the same channel name
2. The last column "Same?" asks the question if the settings are identical in the 2 x BCMs for each channel
3. I've sorted the results by the "Same?" column with "No" first (because these will be of greatest interest to you)
4. There are 2 x types of "No" results: If the 2 x modules genuinely have different values and if the AE BCM does NOT have the channel

Worksheet "AE channels not in AC"

1. Contains a list of channels that appear in the AE BCM - but the same channel is NOT in your AC BCM

As you will see - there are multiple (meaning many) "No Response From Subnet Component" values in your BCM! AFAIK, these BCMs don't have a Subnet!! MQB platform BCMs certainly don't use a Subnet mask because they don't have an IP based network - so the many, many instances of "no response......" in your admap is very strange!

What is the back-story for the BCM in this car? Shirley it can't be the factory installed module - or if it is, has there been some serious software tinkering?

Don

PS: The fog-light Leuchte-sets look OK

[ak77]

Al: hmm.......... that's a mighty odd BCM admap!

What is the back-story for the BCM in this car? Shirley it can't be the factory installed module - or if it is, has there been some serious software tinkering?

Don

PS: The fog-light Leuchte-sets look OK

Thank you Don, I appreciate the help thus far.

No history with the car that I know off. The wife drove for the last 3 years and had little front damage so I opted to upgrade the entire bumper and fog-lights from Gti . This is the TDI 110kw model R edition. So no issues previously.

[ak77]

I'm guessing you are implying this will have to be a firmware update, replacement, or resistors ?

[DV52]

I'm guessing you are implying this will have to be a firmware update, replacement, or resistors ?

No to "firmware update"! As I've said a number of times in this thread, the fact that a 12V signal appears at the fog-light connectors (with the fog-light lamps connected) when the fog-light switch is activated means that the BCM is properly operating the fog-light function. My understanding from your responses is that this happens. So more coding and/or firmware updates won't (shouldn't) change this BCM outcome.

In requesting the BCM admap, I was hopeful that I could spot another reason for this problem. But despite the mighty strange admap that you have provided - none of the weirdness dispels the fact that the BCM is operating the fog-light function correctly at the connectors.

So I'm not sure how familiar you are with electrical theory - but this situation seems to be one where the BCM is supplying the correct voltage, but no electrical current is flowing out of the BCM. If I was looking at this problem anew, I would suspect that the fault was due to incorrectly polarized LEDs. As I assume you already know, LED is short for Light-Emitting-Diode and diodes conduct ONLY if the +ve voltage is connected to the anode lead. If the +ve voltage is instead connected to the diode's cathode lead, the LED won't conduct resulting in "no electrical current flowing"

But, I assume that when you hook-up the temporary battery supply to confirm that the fog-light lamps actually work. you connect the +ve/-ve battery leads to the connector pins with the same pin polarity as the the way that the BCM supplies power.

So, because we have ruled-out coding and reverse-polarity as possible causes for this problem and because you have assured me that the LEDs work properly - I'm scratching my head!!

Don

[ak77]

No to "firmware update"! As I've said a number of times in this thread, the fact that a 12V signal appears at the fog-light connectors (with the fog-light lamps connected) when the fog-light switch is activated means that the BCM is properly operating the fog-light function. My understanding from your responses is that this happens. So more coding and/or firmware updates won't (shouldn't) change this BCM outcome.

In requesting the BCM admap, I was hopeful that I could spot another reason for this problem. But despite the mighty strange admap that you have provided - none of the weirdness dispels the fact that the BCM is operating the fog-light function correctly at the connectors.

So I'm not sure how familiar you are with electrical theory - but this situation seems to be one where the BCM is supplying the correct voltage, but no electrical current is flowing out of the BCM. If I was looking at this problem anew, I would suspect that the fault was due to incorrectly polarized LEDs. As I assume you already know, LED is short for Light-Emitting-Diode and diodes conduct ONLY if the +ve voltage is connected to the anode lead. If the +ve voltage is instead connected to the diode's cathode lead, the LED won't conduct resulting in "no electrical current flowing"

But, I assume that when you hook-up the temporary battery supply to confirm that the fog-light lamps actually work. you connect the +ve/-ve battery leads to the connector pins with the same pin polarity as the the way that the BCM supplies power.

So, because we have ruled-out coding and reverse-polarity as possible causes for this problem and because you have assured me that the LEDs work properly - I'm scratching my head!!

Don

Yes mate above all tried and tested. I really wanted to have the LED lights at fault here but they function isolated outside the BCM. The only other thing I haven't tried is tricking the BCM the I'm still running the halogens by adding resistors.

But honestly mate , you ben excellent and learnt heaps Cheers.
I'm at the give up stage , or so close to it