Help with coding! Reverse Retrofit - Xenon to Aftermarket HL

[dv52 (Australia)]

hmm.......... maybe it's better for you to do the BCM comparison work! I've done the hard part of the exercise for you by creating a BCM compare spreadsheet based on the 2 x BCM admaps that you included in your last reply - open the attachment below

The spreadsheet works like this:

1. The first worksheet contains a side-by-side list of ALL the channels in the new BCM together with the values in the new BCM and the old BCM. 
2. The second worksheet (old BCM without channel match) contains a list of the channels in the old BCM that have NO matching channel name in the new BCM
   
3. The first worksheet, contains a column with the heading "Same?". This column compares the values of each channel between the new BCMs like this:
   
   • If the channel values in the 2 x BCMs is the identical, the entry in the column "Same?" is blank
     
   • If the channel values in the 2 x BCMs is NOT identical, the entry in the column "Same?" is "No"
     

I've sorted the channels in the first worksheet by the entry "No" in the "Same?" column to make your comparison easier because these channels likely will be the reasons for the problems in the car.

There are 2 x reasons for a "No" entry in the "Same?" column

1. The new BCM has an adaptation channel name that does NOT appear in the old BCM
2. The 2 x BCMs have the same adaptation channel name but the values are different
   

You will easily see in the first bunch of channels on the first worksheet how the Leuchte-set values in the old/new BCMs differ
Don

BCM channel compare_goncalves666.xlsx (85 KB)

[goncalves666]

thanks a lot for everything,maybe I'll pay skoda a visit and reflash the new BCM with the proper values for my car.Once again, thanks a lot.

[goncalves666]

Hi,finally got the lights to work properly,couldn't have done it without your assistance,you are just brilliant,thank you so much for all you do for us.

[dv52 (Australia)]

^^^^ Thanks for the generous words and well done!! Just from an intellectual curiosity - what was the eventual fix?

Don

[goncalves666]

Hi,just went through every single adaptation and changed to the value of the old BCM,apparently the new BCM was from a car which came fitted with,bi-xenon,light assist,rear led lights,acc,my car is very basic so every single light had a wrong adaptation.However,some channels in the new BCM where not even present on the old BCM.Will give it another shot and check everything,I'm not even half way through the list you so kindly provided.Once again, thank you so much for your time.
just out of curiosity,do you happen to also know about retrofits and the correct pin out?the whole reason for changing the BCM in the first place was to retrofit heated seats,they are mounted but not yet really working,i followed an installation thread but it was from a seat león,once again same platform,got the seats from a breaker,with the original looms,I'm not sure the pins are OK,as i have a error related to 30,power.Part of the retrofit was adding a pin to BCM A pin 1 to fuse 26,the problem is that BCM A pin 1 and fuse 26 are occupied,there are 2 options,somebody before me installed heated seats and before selling the car removed them,which i found hard to believe or in skoda octavia 3 the power pin goes somewhere else.Also strange because i checked on a friend's octavia with factory mounted sets and pin 26 is in fact heated sets.Or maybe the coding is wrong,but this BCM came from a car with factory mounted heated seats.Can't wrap my head around it.

[dv52 (Australia)]

hmm....... there were 2 x versions of heated seats on MQB platform cars which I call "series" and "parallel" (because of the way that the heating elements were electrically connected) like this:

I'm not sure which version you installed on this car

As for the way that the heated seats are wired back to the BCM, here's an extract from my mk7 wiring diagram for the driver-side seat. Of course, my wiring diagram is NOT the same for an Octavia. What is the exact error message?

As for your dilemma about fuse 26 and BCM pin #1, Socket A - my strong suspicion is that if both were populated with wires on this car - it means that the existing BCM was already factory wired for the T30 supply for seat heating!!! 

Were the large pins for seat heating actually populated on the Sockets on your old BCM?

Don

[goncalves666]

Hi, sorry for the late reply. I was away for the weekend.It turns out the pins were on the wrong places,apparently seat and skoda are on the same platform,but different wire colours,i had a couple of wires wired the wrong way.
Thanks so much for help provided.

[goncalves666]

Hi sorry,didn't really answer ur question,that's the weird part,my bcm didn't have the pins 2 and 5 for the heated seats,but had pin 1 on socket A already wired to the fuse 26,didn't make any sense,called up skoda and according to factory installed bcm it should end on 086 Q,but the one in the actual car was 086 N,which doesn't support heated seats.But Q does,so as i previously thought, maybe the previous owner replaced the seats and bcm?anyway,with your precious help and a couple of phone calls to skoda got things sorted.Once again thank you so much.

[goncalves666]

Hi again,got the cables right,but the error persists. I toke a reading with obdeleven and this is the fault i have. Cannot figure this out.

OBDeleven data log

Date: 2024-08-06 19:22

VIN: TMBJG7NE0E0121695
Car: Skoda Octavia
Year: 2014
Body type: Estate
Engine: CLHA
Mileage: 394567 KM

---------------------------------------------------------------
09 Central Electrics

System description: BCM PQ37BOSCH
Software number: 5Q0937086AK
Software version: 0162
Hardware number: 5Q0937086AK
Hardware version: 028
Serial number: 86581307150185
ODX name: EV_BodyContrModul1UDSBosc
ODX version: 015002
Long coding: 0C02084640C702FB07A04086B10407080008000000000000000000000000

Subsystems:
System description: WWS371 131119
Software version: 0570
Hardware version: 041
Serial number: 131121003114
Long coding: 12E8EE

System description: Sensor, DWA
Software version: 0315
Hardware version: 005
Serial number: 000000000ZY132631CHK

System description: Sirene, DWA
Software version: 0311
Hardware version: 004
Serial number: 00000000000028318788

Trouble codes:
B141113 - Voltage supply, terminal 30 for seat heaters Open circuit
static
Date: 2024-08-02 01:21:24
Mileage: 394567 km
Priority: 1
Malfunction frequency counter: 1
Unlearning counter: 122
Terminal 15 status: On
Terminal 50 status: Off
Voltage: 12.1 V
Outside air temperature: 29.5 °C
Status Bremslichtschalter (HW): Off
Status Bremslichtschalter (CAN): Off
Off: operated
Parking light: not activated
Automatic high beam assist: not activated
Low beam: not activated
Parking light left: not activated
Parking light right: not activated
Letzte Weckursache/ Werte [00;2E]: gültiges Funktelegramm
CAN-Bus_aktiv: On

[dv52 (Australia)]

Alas, I don't have a wiring diagram for this car - so I can't comment. Clearly from your SCAN error - the BCM believes that the T30 supply is missing for the seat heaters. I assume that you have actually tested the physical BCM pin to confirm that the requisite pin is active!

I note that Byte 03 on the BCM = hex46= 01000110. So, Bit 4=0. Bit 3=0, Bit 2=1

Try changing Byte 03 to hex56 = 01010110. So, Bit 4=1. Bit 3=0, Bit 2=1

Don

[q2us3r]

Aug 6, 2024 17:27:33 GMT goncalves666 said:

Hi again,got the cables right,but the error persists. I toke a reading with obdeleven and this is the fault i have. Cannot figure this out.

OBDeleven data log

Date: 2024-08-06 19:22

VIN: TMBJG7NE0E0121695
Car: Skoda Octavia
Year: 2014
Body type: Estate
Engine: CLHA
Mileage: 394567 KM

---------------------------------------------------------------
09 Central Electrics

System description: BCM PQ37BOSCH
Software number: 5Q0937086AK
Software version: 0162
Hardware number: 5Q0937086AK
Hardware version: 028
Serial number: 86581307150185
ODX name: EV_BodyContrModul1UDSBosc
ODX version: 015002
Long coding: 0C02084640C702FB07A04086B10407080008000000000000000000000000

Subsystems:
System description: WWS371 131119
Software version: 0570
Hardware version: 041
Serial number: 131121003114
Long coding: 12E8EE

System description: Sensor, DWA
Software version: 0315
Hardware version: 005
Serial number: 000000000ZY132631CHK

System description: Sirene, DWA
Software version: 0311
Hardware version: 004
Serial number: 00000000000028318788

Trouble codes:
B141113 - Voltage supply, terminal 30 for seat heaters Open circuit
static
Date: 2024-08-02 01:21:24
Mileage: 394567 km
Priority: 1
Malfunction frequency counter: 1
Unlearning counter: 122
Terminal 15 status: On
Terminal 50 status: Off
Voltage: 12.1 V
Outside air temperature: 29.5 °C
Status Bremslichtschalter (HW): Off
Status Bremslichtschalter (CAN): Off
Off: operated
Parking light: not activated
Automatic high beam assist: not activated
Low beam: not activated
Parking light left: not activated
Parking light right: not activated
Letzte Weckursache/ Werte [00;2E]: gültiges Funktelegramm
CAN-Bus_aktiv: On

Did you manage to get to the bottom of this? I have the exact same problem, all is wired correctly as per Erwin (checked multiple times), heated seat elements working (around 1 ohm across heater elements in both seats), BCM supports heated seats (all the necessary pins are present), yet have exactly the same error. Checked that T76A/Pin 1 is definitely receiving Terminal 30 voltage from fuse 26 yet BCM thinks it's not. Could it be a firmware/parametisation issue? maybe BCM needs a firmware upgrade to wake up pin 1.

[ilgidi]

Did you manage to get a fix ? I have the same problem, i have tried everything changing bulbs, check wiring. I think i need to code it but i dont know how.

[q2us3r]

Not yet, still trying to figure it out - are you getting the same error when retrofitting heated seats? I assume you covered the basics and checked that your BCM supports heated seats? (that the required pins are actually there in the BCM).

[ilgidi]

Im having the same problem can you help me please?

[q2us3r]

Aug 19, 2024 9:18:34 GMT ilgidi said:

Im having the same problem can you help me please?

Help you with what? are you also having the same problem with the heated seats? did you check if your BCM supports heated seats?

[ilgidi]

im having the headlights problem

[q2us3r]

Aug 19, 2024 9:24:55 GMT ilgidi said:

im having the headlights problem

That has already been solved in the above thread, the issue was missing adaptation values that were not copied from the old BCM, Once all the adaptation values were the same as in the old BCM all the problems were solved as already discussed by the OP, I suggest you read the thread from the start.

The current discussion is on the issue with the heated seats.

[ilgidi]

how do i copy the old bcm to the new