2013 Audi Allroad MMI Issue

[Onetruth]

Hi All,

I have read A LOT of forum posts regarding issues with MMI and the joys of troubleshooting precisely what the problem might be.

After checking connections, wiring w/ fiber loops, etc. I decided, based on everything I was reading, to purchase a used MMI head unit that matched the model, etc., and replace it.

After the replacement, I saw the following along with the CP, which I know I must have cleared. Still, before I go and do that, I wanted to know if the other items listed in the VCDS scan below are indicative of the CP or held over from my issue with MMI that will likely not be resolved once I get the CP cleared. Thank you in advance for any input.

Scan from original MMI:

4 Faults Found:

00658 - Control Head
004 - No Signal/Communication
Freeze Frame:
Fault Status: 01100100
Fault Priority: 5
Fault Frequency: 1
Reset counter: 220
Mileage: 116920 km
Time Indication: 0
Date: 2024.08.28
Time: 16:50:05
Freeze Frame:
Voltage: 14.30 V

02071 - Local Databus
012 - Electrical Fault in Circuit
Freeze Frame:
Fault Status: 01101100
Fault Priority: 5
Fault Frequency: 1
Reset counter: 220
Mileage: 116920 km
Time Indication: 0
Date: 2024.08.28
Time: 16:50:02
Freeze Frame:
Voltage: 14.20 V

VCDS
Diagnostic Trouble Code Report
Control Module Part Number: 8R1 035 746 K
Page 2

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: 220
Mileage: 116920 km
Time Indication: 0
Date: 2024.08.28
Time: 16:50:04
Freeze Frame:
Voltage: 14.20 V

02259 - Information Display and Control Head (Front) (J685)
008 - Implausible Signal
Freeze Frame:
Fault Status: 01101000
Fault Priority: 5
Fault Frequency: 1
Reset counter: 220
Mileage: 116920 km
Time Indication: 0
Date: 2024.08.28
Time: 16:50:04
Freeze Frame:
Voltage: 14.20 V

Scan from replacement MMI:

5 Faults Found:

00658 - Control Head
004 - No Signal/Communication
Freeze Frame:
Fault Status: 01100100
Fault Priority: 5
Fault Frequency: 1
Reset counter: 220
Mileage: 116920 km
Time Indication: 0
Date: 2024.08.28
Time: 15:36:49
Freeze Frame:
Voltage: 13.90 V

02095 - Component Protection Active
000 - -
Freeze Frame:
Fault Status: 01100000
Fault Priority: 4
Fault Frequency: 1
Reset counter: 220
Mileage: 116920 km
Time Indication: 0
Date: 2024.08.28
Time: 15:36:47

VCDS
Diagnostic Trouble Code Report
Control Module Part Number: 8R1 035 746 K
Page 2

02071 - Local Databus
012 - Electrical Fault in Circuit
Freeze Frame:
Fault Status: 01101100
Fault Priority: 5
Fault Frequency: 1
Reset counter: 220
Mileage: 116920 km
Time Indication: 0
Date: 2024.08.28
Time: 15:36:47

Freeze Frame:
Voltage: 14.00 V

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: 220
Mileage: 116920 km
Time Indication: 0
Date: 2024.08.28
Time: 15:36:50

Freeze Frame:
Voltage: 14.00 V

02259 - Information Display and Control Head (Front) (J685)
008 - Implausible Signal
Freeze Frame:
Fault Status: 01101000
Fault Priority: 5
Fault Frequency: 1
Reset counter: 220
Mileage: 116920 km
Time Indication: 0
Date: 2024.08.28
Time: 15:36:50

Freeze Frame:
Voltage: 14.00 V

# Edited to clean up VCDS text

[Smac770]

"Page 2", never Print, always Save, the autoscan log in VCDS.

The "new unit" codes are all "3:30pm" ish today. The "old unit" codes are all "4:50pm" ish today. Maybe you got the two groups backwards?

Does the MMI come up? CP is not going to stop the MMI from showing up on the screen and you being able to move around in it with the buttons. Does the unit in general appear to function?

Also, after you were all done with any physical changes, did you "clear all DTCs" and then turned off ignition and then turned it back on and played around with the MMI and then did a new scan for whatever codes were new? It would seem so with the today time stamps. But just making sure.

Are these the only errors in the whole vehicle scan? Only errors from 5F, nothing from anything else?

The problem is both error sets show problems with the controls and with the screen. Are you using some intermediate harness (Android system, etc)? Or is this a clean connection between the J794 and the vehicle harness? The screen is connected via a dedicated HSD cable. But the screen has its own power/ground, and that power is fused. Did you check the screen fuse? Fuse 3 in column brown on the passenger end of the dash. The controls on the other hand are just direct wires through the harness to that quad-connector plug.

[Onetruth]

Hi Smac770 thank you for your reply. I'll attempt to answer your questions as succinctly and adequately as possible.

I took the codes in that order. I swapped the original MMI for the new one and ran the scan, I had attempted a swap when I originally got the replacement, but hadn't run a scan. Honestly, I had hoped it would plug and pray and when it hadn't I simply yanked it and let it sit there for a month before I started troubleshooting again. So again. swap > scan > put original back > scan. Hence the time stamps as they are.

The MMI doesn't come up at all. The things that don't work are the MMI screen, backup camera and MMI Controls (with two blinking lights on the right side). I installed an RSNAV unit back in November of last year and it's been working fine ever since until recently. What occured right before the MMI stopped working as described, was that my Allroad had been sitting in the garage and only driven once in a while and weeks in between. I got in one day to drive it and the battery had died. Up until then everything was fine, MMI controls, backup camera. After I jumped the battery and drove it, is when I noticed the controls; power knob etc., because I use them to change tracks and adjust volume. Additionally, I back into my garage, so I would have noticed the backup camera not working before then.

I cleared the DTCs after each swap and ran a fresh scan, each time. I even performed MMI resets in between as well.

Yes, those are the only errors in the scan, nothing else.

As you already know from above, I do have an RSNAV Apple CarPlay 10.5 installed. It's been working fine for months and continues to work to this day. In fact, if I didn't have it installed I'd have no music, nav etc. So I'm thankful that I at least have that to lean while figuring out this issue.

Thank you.

[Smac770]

So many people posting about "car was parked for a while, battery needed to be replaced, car all jacked up now" issues lately.

So you're saying the music is working in the car? Because the radio unit (and amp if B&O) are on the MOST ring with the J794. If the J794 is not working, the whole ring goes down, so there should be no audio. If the car sound system is playing, the MOST ring is working, which means the J794 is up.

Did you check that display unit fuse?

[Onetruth]

Yes, I've read about the battery thing as well. I'm this || close to purchasing a new battery just to rule out any issues with low battery voltage, but I've tested it myself with a multi-meter and it appears to be fine. Car starts fine, etc. One of the first things I did, but did not mention was testing and swapping fuses. Specifically those having to do with the MMI/Radio on the passenger side and in the cargo area.

I'm stumped. Which is why I am here asking more knowledgable folks like yourself for help.

Thank you.

[DrGER]

@Onetruth -- Post your VCDS autoscan log following this guide from Ross-Tech: https://forums.ross-tech.com/index.php?threads/101/

Using a CODE block for this preserves white-space/indenting in the log file, as shown in the Ross-Tech forum post, making it easier for us to scan/interpret quickly.

We're most interested in Addresses 19 (CAN Gateway J533), 47 (Sound System J525), 56 (Radio R), and 5F (Information Electr. J794). --g

[A4Qwattro]

So many people posting about "car was parked for a while, battery needed to be replaced, car all jacked up now" issues lately.

If people know they are going to let the car sit for a while, it's better to disconnect the battery completely. A low battery that is still connected can give the car just enough power to do stupid things to itself. I think people don't like to disconnect the battery because they are afraid of things like keys getting uncoded but in my experience, this doesn't happen on the 8/8.5s. There is nothing material that happens to the electronic systems when you disconnect the battery for a long time.

[Onetruth]

@Onetruth -- Post your VCDS autoscan log following this guide from Ross-Tech: https://forums.ross-tech.com/index.php?threads/101/

Using a CODE block for this preserves white-space/indenting in the log file, as shown in the Ross-Tech forum post, making it easier for us to scan/interpret quickly.

We're most interested in Addresses 19 (CAN Gateway J533), 47 (Sound System J525), 56 (Radio R), and 5F (Information Electr. J794). --g

Hi @DrGER, as requested... thank you.

Thursday,29,August,2024,18:47:10:40264
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 11 x64
VCDS Version: 24.7.0.0 (x64)  HEX-V2 CB: 0.4643.4
Data version: 20240715 DS356.3
www.Ross-Tech.com


VIN: WA1VFAFL4DA245874   License Plate: 
Mileage: 116920km-72650mi   Repair Order: 



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


Chassis Type: FL-AU48 (8R0)
Scan: 01 02 03 05 08 09 15 16 17 19 36 3C 42 44 46 47 52 53 56 5F
          62 6C 6D 72

VIN: WA1VFAFL4DA245874   Mileage: 116920km-72650miles

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
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: OK 0000
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: OK 0000
17-Instruments -- Status: OK 0000
19-CAN Gateway -- 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
62-Door, Rear Left -- Status: OK 0000
6C-Back-up Cam. -- Status: OK 0000
6D-Trunk Elect. -- Status: OK 0000
72-Door, Rear Right -- Status: OK 0000
-------------------------------------------------------------------------------
Address 01: Engine (DET-CPMA)       Labels:. 06H-907-115-CDN.clb
   Part No SW: 8K5 907 115 F    HW: 8K2 907 115 L
   Component: 2.0l R4/4V TF H09 0008  
   Revision: ECH09---    CVN: 511D777D
   Coding: 722A0013242600062000
   Shop #: WSC 53289 003 1048576
   ASAM Dataset: EV_ECM20TFS0118K5907115F 001009
   ROD: EV_ECM20TFS0118K5907115F.rod
   VCID: 353724A2C5C8A222BC5-8060
   VINID: 9D106659159C114442105207105A53BE1D

No fault code found.
Readiness: 1110 0001

-------------------------------------------------------------------------------
Address 02: Auto Trans (J217)       Labels:| 0BK-927-156.clb
   Part No SW: 8K1 927 158     HW: 0BK 927 156 AL
   Component: 0BK 20TFSIUSA H16 1003  
   Revision: --H16---    CVN: 2076C97A
   Coding: 000002
   Shop #: WSC 00000 000 00000
   ASAM Dataset: EV_TCMAL551211 002020
   ROD: EV_TCMAL551211_002_AU48.rod
   VCID: 74B1D9A68E32FB2A4BB-8020

No fault code found.

-------------------------------------------------------------------------------
Address 03: ABS Brakes (J104)       Labels:. 8K0-907-379-V1.clb
   Part No SW: 8K9 907 379 M    HW: 8K9 907 379 M
   Component: ESP8 quattro  H09 0100  
   Revision: --------    Serial number: --------------
   Coding: 0E1D18
   Shop #: WSC 06335 000 00000
   VCID: 4CC16146B6C2C3EAF3B-8018

No fault code found.

-------------------------------------------------------------------------------
Address 05: Acc/Start Auth. (J393)       Labels:. 8K0-907-064-05.clb
   Part No SW: 8K0 907 064 GP    HW: 8K0 907 064 FP
   Component: BCM2 2.0      H12 0633  
   Revision: 00002001    
   Coding: 0D824000000000000000
   Shop #: WSC 06335 000 00000
   VCID: 04518966DE12CBAA7BB-8050

   Subsystem 1 - Part No SW: 8K0 905 852 E    HW: 8K0 905 852 E
   Component: J764 ELV MLB  H40 0046 
   Serial number: 2313000068563005    

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC (J255)       Labels:. 8Kx-820-043-3Z.clb
   Part No SW: 8K1 820 043 T    HW: 8K1 820 043 T
   Component: KLIMA 3 ZONEN H04 0123  
   Revision: C1000000    Serial number: 01250420130110
   Coding: 6480208000
   Shop #: WSC 06335 000 00000
   VCID: 392F2892E950464258D-806C

No fault code found.

-------------------------------------------------------------------------------
Address 09: Cent. Elect. (J519)       Labels:. 8K0-907-063.clb
   Part No SW: 8K0 907 063 DJ    HW: 8K0 907 063 DJ
   Component: BCM1 1.0      H16 0103  
   Revision: 09016001    Serial number: 00000045812601
   Coding: 26000091863CAFC00000480300003D0D0F1C4708A2090221000008004000010200040030000000
   Shop #: WSC 06335 000 00000
   VCID: 7AADF79EACD68D5A117-802E

   Subsystem 1 - Part No SW: 8K1 955 119 A    HW: 8T1 955 119   Labels: 1KX-955-119.CLB
   Component: WWS 200413  H07 0080 
   Serial number: SWF13040206862      
   Coding: 00FD11

   Subsystem 2 - Part No SW: 8U0 955 559 B    HW: 8U0 955 559 B  Labels: 8U0-955-559.CLB
   Component: G397_RLFS  H06 0002 
   Serial number: 21221857            
   Coding: 02005D

   Subsystem 3 - Part No SW: 8K0 941 531 AS    HW: 8K0 941 531 AS
   Component: E1 - LDS  H03 0031 
   Serial number: 00000000001504130421

   Subsystem 4 - Part No SW: 4G0 907 410 A    HW: 4H0 907 410 A
   Component: USHL4.2  H30 0030 
   Serial number: 0000002274555R5NLD02

   Subsystem 5 - Part No SW: 8K5 941 329     HW: 8K5 941 329 
H01 0031 

   Subsystem 6 - Part No SW: 8K5 941 329     HW: 8K5 941 329 
H01 0031 

   Subsystem 7 - Part No SW: 4H0 907 658     HW: 4H0 907 658 
   Component: AQ_Hum_Sensor  H03 0003 
   Serial number: 094984A6000000000001

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags (J234)       Labels:| 8K0-959-655.clb
   Part No SW: 8K0 959 655 M    HW: 8K0 959 655 M
   Component: AirbagVW-AU10 H46 0610  
   Serial number: 003KEDA06TBK   Dataset Number: 8K0909602VA 0001
   Coding: 303844354A32303030304A55304C384B3053
   Shop #: WSC 51539 001 1048576
   ASAM Dataset: EV_AirbaECUVWAUDI010 003010
   ROD: EV_AirbaECUVWAUDI010_003_AU48.rod
   VCID: 47CB5E6AAF2420B2DE9-8012

   Seat occupied recognition: 
   Subsystem 1 - Part No SW: 8K0 959 339 C    HW: 8K0 959 339 C
   Component: BF-Gewichtss.  H02 0040 
   Serial number: 5810000R130000DAV7

   Crash sensor for side airbag: driver side: 
   Serial number: 6334MSME7A717541F

   Front Passenger's Side Airbag Crash Sensor: 
   Serial number: 6344MSME78324D73L

   Rear Side Airbag Crash Sensor (on driver's side): 
   Serial number: 6352QSME1438205AA

   Passenger side rear thorax airbag crash sensor: 
   Serial number: 6362QSME3D302376F

   Crash sensor for front airbag: driver side: 
   Serial number: 63732SME6D30564A3

   Crash sensor for front airbag: front passenger side: 
   Serial number: 63832SME6D30167E7

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel (J527)       Labels:. 8K0-953-568.clb
   Part No SW: 8R0 953 568 Q    HW: 8R0 953 568 Q
   Component: Lenks.Modul   H02 0171  
   Revision: 00000000    Serial number: 20130424001056
   Coding: 000017
   Shop #: WSC 06335 000 00000
   VCID: 4FFB764A47D4F8F2969-801A

   Component: E221 - MFL  H03 0004 

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments (J285)       Labels:. 8T0-920-xxx-17.clb
   Part No SW: 8K0 920 982 D    HW: 8K0 920 982 D
   Component: KOMBIINSTR.   H35 0556  
   Revision: 00400000    Serial number: UVN723C4E     
   Coding: 8BB729020B01D705020000
   Shop #: WSC 06335 123 12345
   VCID: 353724A2C548A222BC5-8060

No fault code found.

-------------------------------------------------------------------------------
Address 19: CAN Gateway (J533)       Labels:. 8T0-907-468.clb
   Part No SW: 8R0 907 468 P    HW: 8R0 907 468 D
   Component: GW-BEM 5CAN-M H11 0056  
   Revision: 1Z110028    Serial number: 2841Z134060188
   Coding: 80C303FF00
   Shop #: WSC 06335 000 00000
   VCID: 4CC16146B6C2C3EAF3B-8018

   Subsystem 1 - Part No SW: 8T0 915 181     HW: 8T0 915 181 
   Component: J367-BDMHella  H03 8041 
   Serial number: 0689070403          

No fault code found.

-------------------------------------------------------------------------------
Address 36: Seat Mem. Drvr (J136)       Labels:. 8T0-959-760.clb
   Part No SW: 8K0 959 760 D    HW: 8K0 959 760 D
   Component: MEM-FS        H06 0076  
   Revision: AA000000    Serial number: 00000056178997
   Coding: 00581B00000000000000
   Shop #: WSC 06335 000 00000
   VCID: 3B23329AE36C74524A1-806E

No fault code found.

-------------------------------------------------------------------------------
Address 3C: Lane Change (J769)       Labels:| 5Q0-907-566.clb
   Part No SW: 8T0 907 566 B    HW: 8T0 907 566 B
   Component: SWA Master    H04 0060  
   Serial number: 0304690307 Dataset Number: 8K0909535J  0030
   Coding: 010211
   Shop #: WSC 05182 002 1048576
   ASAM Dataset: EV_LaneChangAssis 001020
   ROD: EV_LaneChangAssis_AU21.rod
   VCID: 3FDB468AF7F46872669-806A

   Lane change assistance control module 2: 
   Subsystem 1 - Part No SW: 8T0 907 568 B    HW: 8T0 907 568 B
   Component: SWA Slave  H04 0060 
   Serial number: 0302790185          
   Coding: 000102

No fault code found.

-------------------------------------------------------------------------------
Address 42: Door Elect, Driver (J386)       Labels:. 8K0-959-793.clb
   Part No SW: 8K0 959 793 R    HW: 8K0 959 793 P
   Component: TSG FA        H02 0508  
   Revision:             Serial number: 0000058745001 
   Coding: 011C13205E00410001
   Shop #: WSC 06335 000 00000
   VCID: 4FFB764A47D4F8F2969-801A

No fault code found.

-------------------------------------------------------------------------------
Address 44: Steering Assist (J500)       Labels:| 8K0-909-144.clb
   Part No SW: 8K0 909 144 F    HW: 8K0 909 144 B
   Component: RCEPS         H37 0507  
   Revision: 00001000    Serial number: 0014398021 Dataset Number: 8K0909852H  0023
   Coding: 100000000001
   Shop #: WSC 06334 000 00000
   ASAM Dataset: EV_RCEPSAU48X 008014
   ROD: EV_RCEPSAU48X_008.rod
   VCID: 343119A6CEB2BB2A8BB-8060

No fault code found.

-------------------------------------------------------------------------------
Address 46: Central Conv. (J393)       Labels:. 8K0-907-064-46.clb
   Part No SW: 8K0 907 064 GP    HW: 8K0 907 064 FP
   Component: BCM2 2.0      H12 0633  
   Revision: 00002001    Serial number: 0305761764    
   Coding: 0126023A20BA709580B0023200000000
   Shop #: WSC 06334 000 00000
   VCID: 04518966DE12CBAA7BB-8050

   Subsystem 1 - Part No SW: 8K0 959 719 B    HW: 8K0 959 719 
   Component: GTO BF  H01 0080 
   Serial number: 00000000000000661438

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

   Subsystem 3 - Part No SW: 8K0 959 591 B    HW: 8K0 959 591 
   Component: J245 PS150  H08 0043 

   Subsystem 4 - Part No SW: 8K0 959 591 B    HW: 8K0 959 591 
   Component: J394 PS240  H08 0043 

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: 94813013722302
   VCID: 2D070CC22D18EAE2C45-8078

No fault code found.

-------------------------------------------------------------------------------
Address 52: Door Elect, Pass. (J387)       Labels:. 8K0-959-792.clb
   Part No SW: 8K0 959 792 R    HW: 8K0 959 792 P
   Component: TSG BF        H02 0508  
   Revision:             Serial number: 0000057979399 
   Coding: 011C13205E00410001
   Shop #: WSC 06335 000 00000
   VCID: 4EC56B4E40DEF1FA9DF-801A

No fault code found.

-------------------------------------------------------------------------------
Address 53: Parking Brake (----)       Labels: 8K0-907-801-V2.clb
   Part No SW: 8K0 907 801 L    HW: 8K0 907 801 J
   Component: EPB-4         H01 0003  
   Revision: --------    Serial number: 10000000204593
   ASAM Dataset: EV_ParkiBrake 001027
   ROD: EV_ParkiBrake_AU48.rod
   VCID: 38292D96D2DA5F4AA73-806C

No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio (R)       Labels:. 4F0-035-0xx-56.clb
   Part No SW: 4G0 035 082 H    HW: 4G0 035 082 
   Component: Radio U SIRIU H60 0138  
   Revision: AB001007    Serial number: 156D60D7717976
   Coding: 020007010000000001
   Shop #: WSC 06335 000 00000
   VCID: 2517F4E275E8D2A20C5-8070

No fault code found.

-------------------------------------------------------------------------------
Address 5F: Information Electr. (J794)       Labels:. 4E0-035-6xx-5F.clb
   Part No SW: 8R1 035 746 K    HW: 8R1 035 746 B
   Component: H-BNT-NA      H44 1040  
   Revision: --------    Serial number: 204D+0D7574856
   Coding: 010200050006A1EF51028B4E00000403140000000000000000
   Shop #: WSC 06335 000 00000
   VCID: 3FDB468AF7746872669-806A

   Subsystem 1 - Part No: 8R0 060 884 BA
   Component: NAR 2013  0703 

   Subsystem 2 - Part No: 8R0 060 961 E
   Component: CD-Database  4949 

4 Faults Found:
00658 - Control Head 
            004 - No Signal/Communication
             Freeze Frame:
                    Fault Status: 01100100
                    Fault Priority: 5
                    Fault Frequency: 1
                    Reset counter: 220
                    Mileage: 116920 km
                    Time Indication: 0
                    Date: 2024.08.28
                    Time: 16:50:05

             Freeze Frame:
                    Voltage: 14.30 V

02071 - Local Databus 
            012 - Electrical Fault in Circuit
             Freeze Frame:
                    Fault Status: 01101100
                    Fault Priority: 5
                    Fault Frequency: 1
                    Reset counter: 220
                    Mileage: 116920 km
                    Time Indication: 0
                    Date: 2024.08.28
                    Time: 16:50:02

             Freeze Frame:
                    Voltage: 14.20 V

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: 220
                    Mileage: 116920 km
                    Time Indication: 0
                    Date: 2024.08.28
                    Time: 16:50:04

             Freeze Frame:
                    Voltage: 14.20 V

02259 - Information Display and Control Head (Front) (J685) 
            008 - Implausible Signal
             Freeze Frame:
                    Fault Status: 01101000
                    Fault Priority: 5
                    Fault Frequency: 1
                    Reset counter: 220
                    Mileage: 116920 km
                    Time Indication: 0
                    Date: 2024.08.28
                    Time: 16:50:04

             Freeze Frame:
                    Voltage: 14.20 V


-------------------------------------------------------------------------------
Address 62: Door, Rear Left (J388)       Labels:. 8K0-959-795.clb
   Part No SW: 8K0 959 795 G    HW: 8K0 959 795 D
   Component: TSG HL        H01 0506  
   Revision:             Serial number: 0000058969521 
   Coding: 010C13204000210001
   Shop #: WSC 06335 000 00000
   VCID: 46D5536EA8AE39BA25F-8012

No fault code found.

-------------------------------------------------------------------------------
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: --H07---    Serial number: 525PA8-J3290B8
   Coding: 1000007
   Shop #: WSC 06335 000 00000
   VCID: 38292D96DE5A5F4AA73-806C

No fault code found.

-------------------------------------------------------------------------------
Address 6D: Trunk Elect. (J605)       Labels: 8K9-827-851.clb
   Part No SW: 8K9 827 851 A    HW: 8K9 827 851 A
   Component: J605  Master  H52 0330  
   Revision: --------    Serial number: 8K9827851A    
   VCID: 3C213186E662736A43B-8068

   Subsystem 1 - Part No SW: 8K9 827 852 A    HW: 8K9 827 852 A
   Component: J756  Slave  H52 0330 
   Serial number: 8K9827852A          

No fault code found.

-------------------------------------------------------------------------------
Address 72: Door, Rear Right (J389)       Labels:. 8K0-959-795.clb
   Part No SW: 8K0 959 795 G    HW: 8K0 959 795 D
   Component: TSG HR        H01 0506  
   Revision:             Serial number: 0000058969522 
   Coding: 010C13204000210001
   Shop #: WSC 06335 000 00000
   VCID: 46D5536EA8AE39BA25F-8012

No fault code found.

End----------(Elapsed Time: 02:00, VBatt start/end: 14.4V/14.4V)-----------

[Smac770]

The log shows the J533 can interact with and query the MOST ring members, so the ring is not down.

That you have RSNAV Android tablet aftermarket display, that makes this a completely different approach than a stock vehicle. And whatever assumptions led you to assume the issue was the J794 may or may not be relevant in an RSNAV configuration. We can't know what the problems are with the interaction between the RSNAV and the J794. It sounds basically like the RSNAV has checked out. The J794 says it cannot talk to the display, which is the RSNAV, not the J685 like a normal car.

Do you have your old screen? I'd say step one would be to remove the RSNAV intermediate harness and connect the car harness directly to the J794. And run the display cable (and the power/ground cable) to the real J685 and see what you get. If everything is functional as expected, then you put the RSNAV config back and see what happens.

[DrGER]

I agree with SMac. After-market CP/AA solutions like RSNAV use wire harness adapters to re-route connections to/from the J794 main unit. Your main unit can't reach the control head/console E380 and finds a fault in the (entertainment) CAN bus, which are likely affected by the RSNAV control module and its wire harness adapter. --g

[Smac770]

Remember, the MMI vehicles have no infotainment CAN bus. The infotainment bus is the MOST ring. That's why when someone on the ring breaks, now you can't talk to anything to find out what's going on.

The local databus error is about the LIN bus between the J794 control module and the J685 screen (the four signals on the HSD are lvds+, lvds-, LIN, and ground). "local databus" means LIN in the Audi errors.

[Onetruth]

Thanks for the suggestion gents. I figured that would be something I would need to attempt eventually. I went in today and disconnected the RSNAV harness and screen, etc. I then reconnected the original screen. When I did that everything worked. MMI controls worked, backup camera, MMI screen.

I am wondering if it's the harness between the RSNAV and the MMI. I think it would be worth a try to replace that piece, if cost effective, before I ditched the whole thing. As is, I can leave the RSNAV in place, but I won't have MMI controls or backup camera. If I yank it, I'll go back to stock NAV and music over bluetooth, as before.

Thank you both for your assistance and ultimately getting me to a place I should have gone prior to reaching out. I hope others can learn from our interaction. I'll update if I decide to get a replacement harness and it fixes the issue, although it may be the RSNAV unit itself given I can't see a drained battery causing issues with the harness itself, but more likely the RSNAV. IMHO.

Thanks again, it's great having people like you on here willing to help as much as you did.

[Smac770]

Yeah, at this point, your concern is "is the RSNAV unit itself ok", or is it a harness issue. Because take the video connection, don't you simply run it into the RSNAV instead of the J685? Yet the J794 said it could not interact with the "screen". So was the RSNAV actually unpowered because of a wiring harness issue? Does the RSNAV actually intercept the signal from the E380 controls or does it just tap into them? I don't have one so can't validate how all that actually happens. If it's just a harness issue getting power to the RSNAV or such, wiring is easy. But if the RSNAV itself is shot (I have no idea if there's a way to see it actually working or not on a bench), that's a much more expensive concern.

The Concert radio unit had a fuse built into itself that a lot of people wouldn't know of when it was not working. The RSNAV might have some kind of similar internal mechanism (or inline fuse or breaker) that might need some kind of reset or replacement if you can't see the RSNAV itself is clearly powering up with 12v applied.

[DrGER]

Thanks for the clarification on the local databus fault. Re communication with the E380 control head, consider this document of the generic Chinese CP/AA module from 2018: https://f00.psgsm.net/product/894280...udi-manual.pdf
It looks to me like these intercept the serial communication from/to the control head at terminals 10 & 11 of connector T16q of the QuadLock. I suspect the RSNAV operates in a similar fashion. --g