High Beam Assist Retrofit Test

[Broteinshake]

Hi,
I'm trying to install a salvaged high beam assist rear view mirror from a 2014 A8 into my 2016 S5.
I have side assist in the S5 so I know I have extended CAN.
I used the following wiring diagram but I cant seem to get the car to communicate with the high beam assist module at address 20.
Any ideas? Is my "test" cabling to blame? My S5 already had the 8-pin adapter standard but didn't have the wire going to the canbus module so I just used alligator clips before making permanent alterations.
I have an RSnav screen installed also, which is causing a few mmi related errors.

Saturday,07,August,2021,11:21:32:10319
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 20.12.0.1 (x64)  HEX-V2 CB: 0.4529.4
Data version: 20201125 DS322.1
www.Ross-Tech.com


VIN: WAUC4AFR7GA035679   License Plate:
Mileage: 53890km-33485mi   Repair Order:



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: FR-AU48 (8R0)
Scan: 01 02 03 05 06 08 09 15 16 17 19 20 22 36 3C 42 44 46 47 52
          53 56 5F 6C A9

VIN: WAUC4AFR7GA035679   Mileage: 53890km-33485miles

01-Engine -- Status: OK 0000
02-Auto Trans -- Status: OK 0000
03-ABS Brakes -- Status: OK 0000
04-Steering Angle -- Status: OK 0000
05-Acc/Start Auth. -- Status: OK 0000
06-Seat Mem. Pass -- Status: OK 0000
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: Malfunction 0010
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: OK 0000
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: Malfunction 0010
20-High Beam Assist. -- Status: OK 0000
22-AWD -- Status: OK 0000
36-Seat Mem. Drvr -- Status: OK 0000
3C-Lane Change -- Status: OK 0000
42-Door Elect, Driver -- Status: OK 0000
44-Steering Assist -- Status: OK 0000
46-Central Conv. -- Status: OK 0000
47-Sound System -- Status: OK 0000
52-Door Elect, Pass. -- Status: OK 0000
53-Parking Brake -- Status: OK 0000
56-Radio -- Status: OK 0000
5F-Information Electr. -- Status: Malfunction 0010
6C-Back-up Cam. -- Status: OK 0000
A9-Struct. Borne Sound -- Status: OK 0000
-------------------------------------------------------------------------------
Address 01: Engine (J623-CTUB)       Labels:. 06E-907-551-CGW.clb
   Part No SW: 8K5 907 551 G    HW: 4G0 907 551 A
   Component: 3.0l V6 TFSIH07 0007
   Revision: --H07---
   Coding: 1A250034052600060000
   Shop #: WSC 06208 000 00000
   ASAM Dataset: EV_ECM30TFS0218K5907551G 001007
   ROD: EV_ECM30TFS021_AU48.rod
   VCID: 3A2D3757BCDD1D2B7D6-806E

No fault code found.
Readiness: 1110 1101

-------------------------------------------------------------------------------
Address 02: Auto Trans (J217)       Labels:| 0B5-927-156.clb
   Part No SW: 8K5 927 156 D    HW: 0B5 927 156 K
   Component: 0B5 30TFSINAR H03 0004
   Revision: --H03---
   Coding: 000001
   Shop #: WSC 06325 000 00000
   ASAM Dataset: EV_TCMDL501021 001015
   ROD: EV_TCMDL501021.rod
   VCID: 3A2D3757BCDD1D2B7D6-806E

No fault code found.

-------------------------------------------------------------------------------
Address 03: ABS Brakes (J104)       Labels:. 8K0-907-379-V2.clb
   Part No SW: 8K0 907 379 CP    HW: 8K0 907 379 CP
   Component: ESP8 quattro  H09 0020
   Revision: --------    Serial number: --------------
   Coding: 291D1A01
   Shop #: WSC 06325 000 00000
   VCID: 094F989BA93BC6B324C-805C

No fault code found.

-------------------------------------------------------------------------------
Address 05: Acc/Start Auth. (J393)       Labels:. 8K0-907-064-05.clb
   Part No SW: 8K0 907 064 KM    HW: 8K0 907 064 KM
   Component: BCM2 2.0      H15 0711
   Revision: 00002001
   Coding: 0D804040000000000000
   Shop #: WSC 06325 000 00000
   VCID: 055794AB8523A2D3404-8050

   Subsystem 1 - Part No SW: 8K0 905 852 E    HW: 8K0 905 852 E
   Component: J764 ELV MLB  H40 0046
   Serial number: 3215000169184006

No fault code found.

-------------------------------------------------------------------------------
Address 06: Seat Mem. Pass (J521)       Labels:. 8T0-959-760.clb
   Part No SW: 8T0 959 760 E    HW: 8T0 959 760 E
   Component: MEM-BFS       H10 0077
   Revision: AA000000    Serial number: 00000174511490
   Coding: 00037025002C00000000
   Shop #: WSC 06325 000 00000
   VCID: 45D754ABC5A362D3004-8010

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC (J255)       Labels:. 8Kx-820-043-3Z.clb
   Part No SW: 8K1 820 043 AQ    HW: 8K1 820 043 AQ
   Component: KLIMA 3 ZONEN H04 0122
   Revision: C1000000    Serial number: 01191120152158
   Coding: 6602228000
   Shop #: WSC 06325 123 12345
   VCID: 77ABEE63CFCFC043428-8022

No fault code found.

-------------------------------------------------------------------------------
Address 09: Cent. Elect. (J519)       Labels:. 8K0-907-063.clb
   Part No SW: 8K0 907 063 DH    HW: 8K0 907 063 DH
   Component: BCM1 1.0      H16 0103
   Revision: 08016001    Serial number: 00001214019001
   Coding: 26000091867CAFE0210048C300003D0D0F9CD388AA090221000008004000030100000030000000
   Shop #: WSC 06325 123 12345
   VCID: 78A9ED5FC2D1CF3B4B2-802C

   Subsystem 1 - Part No SW: 8T1 955 119 D    HW: 8J1 955 119   Labels: 1KX-955-119.CLB
   Component: WWS 191115  H15 0080
   Serial number: SWF15111195215  
   Coding: 00FD11

   Subsystem 2 - Part No SW: 8U0 955 559 C    HW: 8U0 955 559 B  Labels: 8U0-955-559.CLB
   Component: G397_RLFS  H06 0004
   Serial number: 60967850        
   Coding: 02005D

   Subsystem 3 - Part No SW: 8K0 941 531 AS    HW: 8K0 941 531 AS
   Component: E1 - LDS  H03 0031
   Serial number: 00000000000611151767

   Subsystem 4 - Part No SW: 4G0 907 410 A    HW: 4H0 907 410 A
   Component: USHL4.2  H30 0030
   Serial number: 00000000095Z0218019C

   Subsystem 5 - Part No SW: 4H0 907 658     HW: 4H0 907 658
   Component: AQ_Hum_Sensor  H03 0003
   Serial number: F469CCD7000000000001

1 Fault Found:
03395 - Control Module for High Beam Assistant
            004 - No Signal/Communication
             Freeze Frame:
                    Fault Status: 01100100
                    Fault Priority: 6
                    Fault Frequency: 1
                    Reset counter: 74
                    Mileage: 53891 km
                    Time Indication: 0
                    Date: 2021.08.07
                    Time: 11:17:54


-------------------------------------------------------------------------------
Address 15: Airbags (J234)       Labels:| 8K0-959-655.clb
   Part No SW: 8K0 959 655 Q    HW: 8K0 959 655 Q
   Component: AirbagVW-AU10 H53 0812
   Serial number: 003NDD20DS2B
   Coding: 303343334830383131304A55304C38543053
   Shop #: WSC 06325 000 00000
   ASAM Dataset: EV_AirbaECUVWAUDI010 003114
   ROD: EV_AirbaECUVWAUDI010_003_AU48.rod
   VCID: 4BC36293E34794A3D60-801E

   Seat occupied recognition:
   Subsystem 1 - Part No SW: 8K0 959 339 A    HW: 8K0 959 339 A
   Component: BF-Gewichtss.  H02 0060
   Serial number: 5810000R150000PYG4

   Crash sensor for side airbag: driver side:
   Serial number: 6334MSME541C11074

   Front Passenger's Side Airbag Crash Sensor:
   Serial number: 6344MSME5479061CI

   Rear Side Airbag Crash Sensor (on driver's side):
   Serial number: 6352QSME724F4954R

   Passenger side rear thorax airbag crash sensor:
   Serial number: 6362QSME5D572840M

   Crash sensor for front airbag: driver side:
   Serial number: 63732SME5F525144/

   Crash sensor for front airbag: front passenger side:
   Serial number: 63832SME65524A52$

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel (J527)       Labels:. 8K0-953-568.clb
   Part No SW: 8K0 953 568 M    HW: 8K0 953 568 M
   Component: Lenks.Modul   H04 0005
   Revision: --------    Serial number: 90372OKD000H1
   Coding: 000036
   Shop #: WSC 06325 000 00000
   VCID: 44D149AFCE995BDB17A-8010

   Component: E221 - MFL  H03 0004

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments (J285)       Labels:. 8T0-920-xxx-17.clb
   Part No SW: 8T0 920 984 F    HW: 8T0 920 984 F
   Component: KOMBIINSTR.   H35 0567
   Revision: 00100000    Serial number: 5PM407DCG  
   Coding: 8BB701008301D705020000
   Shop #: WSC 06325 000 00000
   VCID: 42DD4FB7D48D55EB256-8016

No fault code found.

-------------------------------------------------------------------------------
Address 19: CAN Gateway (J533)       Labels:. 8T0-907-468.clb
   Part No SW: 8R0 907 468 AA    HW: 8R0 907 468 D
   Component: GW-BEM 5CAN-M H11 0070
   Revision: 1Z130032    Serial number: 3241Z15B11057D
   Coding: 80C303FF00
   Shop #: WSC 06325 000 00000
   VCID: 7EA5FB47E0F5F10B01E-802A

   Subsystem 1 - Part No SW: 8T0 915 181     HW: 8T0 915 181
   Component: J367-BDMHella  H03 8041
   Serial number: 8026328503      

1 Fault Found:
02001 - Data-Bus Automatic Distance Regulation
            014 - Defective
             Freeze Frame:
                    Fault Status: 01101110
                    Fault Priority: 1
                    Fault Frequency: 1
                    Reset counter: 74
                    Mileage: 53891 km
                    Time Indication: 0
                    Date: 2021.08.07
                    Time: 11:17:54

             Freeze Frame:
                    Bin. Bits:    10111
                    Voltage: 11.60 V
                    Count: 6
                    Bin. Bits:    10000


-------------------------------------------------------------------------------
Address 20: High Beam Assist.
Cannot be reached

-------------------------------------------------------------------------------
Address 22: AWD (J492)       Labels: 8K0-907-163.clb
   Part No SW: 8K0 907 163 B    HW: 8K0 907 163 A
   Component: 4 Wheel Drive H15 0100
   Serial number: 001311150001085
   ASAM Dataset: EV_AllWheelDiffeQSPCAN 003019
   ROD: EV_AllWheelDiffeQSPCAN.rod
   VCID: 2F3B1603779FC883DA8-807A

No fault code found.

-------------------------------------------------------------------------------
Address 36: Seat Mem. Drvr (J136)       Labels:. 8T0-959-760.clb
   Part No SW: 8T0 959 760 E    HW: 8T0 959 760 E
   Component: MEM-FS        H10 0077
   Revision: AA000000    Serial number: 00000175760163
   Coding: 001B7B25002C00000000
   Shop #: WSC 06325 000 00000
   VCID: 45D754ABC5A362D3004-8010

No fault code found.

-------------------------------------------------------------------------------
Address 3C: Lane Change
Cannot be reached

-------------------------------------------------------------------------------
Address 42: Door Elect, Driver (J386)       Labels:. 8K0-959-793.clb
   Part No SW: 8T0 959 793 P    HW: 8T0 959 793 G
   Component: TSG FA        H10 0305
   Revision: --------    Serial number: --------------
   Coding: 011C13224E00120102
   Shop #: WSC 06325 000 00000
   VCID: 56F583E72805D94B79E-8002

No fault code found.

-------------------------------------------------------------------------------
Address 44: Steering Assist (J500)       Labels:| 8K0-909-144.clb
   Part No SW: 8K0 909 144 Q    HW: 8K0 909 144 L
   Component: RCevo         H53 0702
   Revision: 00000003    Serial number: 0000396577
   Coding: 100000010001
   Shop #: WSC 06324 000 00000
   ASAM Dataset: EV_RCEPSAU48X 104002
   ROD: EV_RCEPSAU48X_104.rod
   VCID: 3FDB4643A7FF38034A8-806A

No fault code found.

-------------------------------------------------------------------------------
Address 46: Central Conv. (J393)       Labels:. 8K0-907-064-46.clb
   Part No SW: 8K0 907 064 KM    HW: 8K0 907 064 KM
   Component: BCM2 2.0      H15 0711
   Revision: 00002001    Serial number: 0385986635
   Coding: 0106069A00FA400583B0003200000000
   Shop #: WSC 06324 123 12345
   VCID: 055794AB8523A2D3404-8050

   Subsystem 1 - Part No SW: 8K0 959 719 B    HW: 8K0 959 719
   Component: GTO BF  H01 0080
   Serial number: 00000000000001073978

   Subsystem 2 - Part No: 1K0 951 605 C
   Component: LIN BACKUP HO  H05 1501

   Subsystem 3 - Part No SW: 8R0 959 591 A    HW: 8R0 959 591
   Component: J245EE20SKB13  H06 0220
   Serial number: 0123456789ABCDEFGHIJ

No fault code found.

-------------------------------------------------------------------------------
Address 47: Sound System (J525)       Labels:. 8T0-035-223-BOM.clb
   Part No SW: 8T1 035 223 A    HW: 8T1 035 223 A
   Component: DSP Prem      H05 0030
   Revision: 00005001    Serial number: 94813052904607
   VCID: 2D070C0B7D13BA93E84-8078

No fault code found.

-------------------------------------------------------------------------------
Address 52: Door Elect, Pass. (J387)       Labels:. 8K0-959-792.clb
   Part No SW: 8T0 959 792 P    HW: 8T0 959 792 G
   Component: TSG BF        H10 0305
   Revision: --------    Serial number: --------------
   Coding: 011C13224E00120102
   Shop #: WSC 06325 000 00000
   VCID: 55F784EB3503D253704-8000

No fault code found.

-------------------------------------------------------------------------------
Address 53: Parking Brake (----)       Labels: 8K0-907-801-V2.clb
   Part No SW: 8K0 907 801 N    HW: 8K0 907 801 J
   Component: EPB-4         H02 0005
   Revision: --------    Serial number: 30000000449269
   ASAM Dataset: EV_ParkiBrake 001028
   ROD: EV_ParkiBrake_AU48.rod
   VCID: 3A2D3757BCDD1D2B7D6-806E

No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio (R)       Labels: Redir Fail!
   Part No SW: 4G0 035 082 G    HW: 4G0 035 082
   Component: Radio U SIRIU H66 0133
   Revision: AB001007    Serial number: 156K-0F2522641
   Coding: 020007010000000001
   Shop #: WSC 06325 000 00000
   VCID: 2411E92F2ED97BDB37A-8070

No fault code found.

-------------------------------------------------------------------------------
Address 5F: Information Electr. (J794)       Labels:. 4E0-035-6xx-5F.clb
   Part No SW: 8R1 035 746 J    HW: 8R1 035 746 G
   Component: H-BNT-NA      H43 0952
   Revision: --------    Serial number: 523KF0FS015741
   Coding: 140200020206A1EF55028B5E00000403140000000000000000
   Shop #: WSC 06325 123 12345
   VCID: 3E253B47A075310B41E-806A

   Subsystem 1 - Part No: 8R0 060 884 DG
   Component: NAR 2016  1302

   Subsystem 2 - Part No SW: 8T0 919 611 K    HW: 8T0 919 611 B
   Component: E0380 Bedient  H02 0030
   Serial number:        2696164  

   Subsystem 3 - Part No: 8R0 060 961 G
   Component: CD-Database  6890

3 Faults Found:
03389 - Data Set Implausible
            000 - -
             Freeze Frame:
                    Fault Status: 01100000
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 74
                    Mileage: 53891 km
                    Time Indication: 0
                    Date: 2021.08.07
                    Time: 11:17:57

             Freeze Frame:
                    Voltage: 11.40 V
                    Bin. Bits:      010

03157 - Functionality limited due to Communications Disruption
            000 - -
             Freeze Frame:
                    Fault Status: 01100000
                    Fault Priority: 6
                    Fault Frequency: 1
                    Reset counter: 74
                    Mileage: 53891 km
                    Time Indication: 0
                    Date: 2021.08.07
                    Time: 11:17:59

             Freeze Frame:
                    Bin. Bits: 00000000 00000000
                    Bin. Bits: 00000100 00000000
                    Bin. Bits: 00000000 00000000
                    Bin. Bits: 00000000 00000000
                    Bin. Bits: 00000000 00000000

02259 - Information Display and Control Head (Front) (J685)
            004 - No Signal/Communication
             Freeze Frame:
                    Fault Status: 01100100
                    Fault Priority: 5
                    Fault Frequency: 1
                    Reset counter: 74
                    Mileage: 53891 km
                    Time Indication: 0
                    Date: 2021.08.07
                    Time: 11:18:00

             Freeze Frame:
                    Voltage: 11.30 V


-------------------------------------------------------------------------------
Address 6C: Back-up Cam.        Labels: 8T0-907-441.clb
   Part No SW: 8T0 907 441 C    HW: 4L0 907 441 B
   Component: J772__Rearview      0040
   Revision: --H09---    Serial number: 525PA8-JA990Q8
   Coding: 1000008
   Shop #: WSC 06325 000 00000
   VCID: 38292D5F8E510F3B8B2-806C

No fault code found.

-------------------------------------------------------------------------------
Address A9: Struct. Borne Sound (J869)       Labels: 4H0-907-159.clb
   Part No SW: 8K0 907 159     HW: 4H0 907 159 A
   Component: SAS-GEN 2     H06 0006
   Serial number: 151007201024
   ASAM Dataset: EV_SoundActuaGen2AU64X 003010
   ROD: EV_SoundActuaGen2AU64X.rod
   VCID: 72BDDF77A42DA56B756-8026

No fault code found.

End----(Elapsed Time: 01:47, VBatt start/end: 11.4V/11.3V. VIgn 11.4V)-----

https://imgur.com/a/X7ymZxg

https://imgur.com/a/De0CkHJ

 

[Zenerdiode]

Well, being pedantic, CAN wiring is supposed to be twisted at a rate of roughly one twist to 10mm. I don’t know in a practical situation if your 1m red and black test leads would bring down the bus not being twisted.

Please re-check your CAN wiring. The tracer colours on the orange CAN wires are subtle and easily confused. CAN-Low on all networks are the same colour - for example. Are you sure you’re connecting to the correct CAN?

If you disconnect your temporary CAN extension, does module 3C come back online; and module 19 error becomes intermittent?

 

[Uwe]

CAN wiring is supposed to be twisted at a rate of roughly one twist to 10mm.

I doubt it makes a difference over that short a distance, but we've had good luck extending CAN signals over several tens of meters using one twisted pair of a typical CAT5 cable.

-Uwe-

 

[DV52]

Well, being pedantic, CAN wiring is supposed to be twisted at a rate of roughly one twist to 10mm.

@Zenerdiode: in my world, "pedantic" is good!!!

I didn't know about "one twist to 10mm" - I'm aware that the twist rate (pitch?) determines the wires' effective impedance - but is the 10 mm value set by the max Bit-rate of CAN signals, or is it a result of conductor size, or a characteristic of the likely interference signals (or a combination)? Where is the number codified?

Don

 

[m87a]

@Zenerdiode: in my world, "pedantic" is good!!!

I didn't know about "one twist to 10mm" - I'm aware that the twist rate (pitch?) determines the wires' effective impedance - but is the 10 mm value set by the max Bit-rate of CAN signals, or is it a result of conductor size, or a characteristic of the likely interference signals (or a combination)? Where is the number codified?

Don

i have tested and used 2 regular wires for can, not twisted without issues, no problem with diagnostics or communication issues, so i'm not sure it does affect speed, and or interference. I have retrofitted high led lights instead of basic led and had extra wires which i have used as a can for test and everything worked ok, owner asked me to just finish as soon as possible because he had to travel. I was prepared to run 2 additional can wires later but he didn't have any issue or dtc, so it stayed like that.
Sorry for going off topic, but test power, ground and can that should be it.

 

[DV52]

@m87a: Thanks for the response - I like real life examples that defy theory (it makes me question my understanding of why stuff is designed as it is - which is always a good thing)!!
Many years ago, I spent some time working in the very arcane area of lightning protection for tall buildings. The time made me appreciate the value of "frequency impedance" (similar to "characteristic impedance") of simple wires. In the case of a lighting strike - the incredibly fast rise time of the voltage pulse made even the slightest bend in a seemingly straight conductor look like an inductor. It entirely changed the ability of the wire to attract lighting strikes.
I suspect that the pitch of twisted-pair CAN wires is similar but opposite in that the inductor/capacitor effect is to filter rather than attract external signal(s) (at much lower frequencies, of course) - but I'm guessing.

@Broteinshake: Please accept my apology too for jacking your thread - but in respect of your make-shift, alligator-clip CAN pair, did you ensure that the polarity was correct (i.e. CAN-high & CAN-low lines were connected appropriately)?

 

[Broteinshake]

@m87a: Thanks for the response - I like real life examples that defy theory (it makes me question my understanding of why stuff is designed as it is - which is always a good thing)!!
Many years ago, I spent some time working in the very arcane area of lightning protection for tall buildings. The time made me appreciate the value of "frequency impedance" (similar to "characteristic impedance") of simple wires. In the case of a lighting strike - the incredibly fast rise time of the voltage pulse made even the slightest bend in a seemingly straight conductor look like an inductor. It entirely changed the ability of the wire to attract lighting strikes.
I suspect that the pitch of twisted-pair CAN wires is similar but opposite in that the inductor/capacitor effect is to filter rather than attract external signal(s) (at much lower frequencies, of course) - but I'm guessing.

@Broteinshake: Please accept my apology too for jacking your thread - but in respect of your make-shift, alligator-clip CAN pair, did you ensure that the polarity was correct (i.e. CAN-high & CAN-low lines were connected appropriately)?

yeah i triple checked. Does the canbus communication only go one way? as in the mirror is just sending a signal to the j533 unit? or is there some kind of loop that its on? i also think that the mirror speaks "flexray" instead of the compatible canbus programming that could be the issue now that I think about it

 

[Broteinshake]

Well, being pedantic, CAN wiring is supposed to be twisted at a rate of roughly one twist to 10mm. I don’t know in a practical situation if your 1m red and black test leads would bring down the bus not being twisted.

Please re-check your CAN wiring. The tracer colours on the orange CAN wires are subtle and easily confused. CAN-Low on all networks are the same colour - for example. Are you sure you’re connecting to the correct CAN?

If you disconnect your temporary CAN extension, does module 3C come back online; and module 19 error becomes intermittent?

I actually never noticed 3c was offline. I put it all back together without my jerry-rig and 3c was fine when i communicated with it. Ill use an ethernet cord next time with some zip ties lmao. Do i literally just splice them into the same wire the lane change assist is on? like wire to wire? I feel like there needs to fundamentally be some sort of "junction" instead of something so crude.

 

[DV52]

Does the canbus communication only go one way?

No- CAN is a fully fledged 2 x way communication protocol (serial)

as in the mirror is just sending a signal to the j533 unit? or is there some kind of loop that its on?

Maybe read SSP 186 (google it). And perhaps a better way of thinking about J533 is like it's the Fat-controller of Tomas-the-Tank-Engine fame (in that the hex 19 module is more akin to a traffic coordinator for messaging across and within CAN buses). J533 has a quite separate role for the diagnostic function

i also think that the mirror speaks "flexray" instead of the compatible canbus programming that could be the issue now that I think about it

hmm......... you might want to confirm this suspicion as a priority

Do i literally just splice them into the same wire the lane change assist is on? like wire to wire? I feel like there needs to fundamentally be some sort of "junction" instead of something so crude.

I don't have a CAN network diagram for your car - but assuming that hex3C and hex20 modules share a common CAN bus. yes - it really is that "crude"

 

[Broteinshake]

No- CAN is a fully fledged 2 x way communication protocol (serial)

Maybe read SSP 186 (google it). And perhaps a better way of thinking about J533 is like it's the Fat-controller of Tomas-the-Tank-Engine fame (in that the hex 19 module is more akin to a traffic coordinator for messaging across and within CAN buses). J533 has a quite separate role for the diagnostic function

hmm......... you might want to confirm this suspicion as a priority

I don't have a CAN network diagram for your car - but assuming that hex3C and hex20 modules share a common CAN bus. yes - it really is that "crude"

Do you know where I would get the CAN network diagram? Or do you know of an easier place to tap into the can network for a test fit to see if i can get it to communicate? I kinda don't want to keep taking my glovebox in and out. Vin is WAUC4AFR7GA035679

 

[Broteinshake]

I made my own from russian elsawin.
I guess i can just tap into it from the passenger footwell at connector T17f.

https://imgur.com/a/ctpGEyz

 

[DV52]

Do you know where I would get the CAN network diagram?

Maybe read SSP 395: Audi A5 - Networking (Google it)

 

[rapier]

I'd say it's definitely a wiring issue. Does your auto dimming mirror work ? Was it standard? If so have you changed the reverse feed pin to one of the canbus feeds,