Audi C7 A6 - No ignition, Modules "cannot be reached

[its_tcs]

Hi everyone!


My name is Tom. New to this forum, but I have found it a valuable resource over the years.


I recently bought a C7 A6 Avant at auction, 2.0 TDI CNHA engine. It needed a set of injectors -which I have now changed- and a new battery. After driving it for about 60 miles another issue has arisen, however.


The ignition does not turn on anymore. After getting in (central locking still works) the A6 screen flashes on the the dash, but after that nothing. No response to the start/stop button, MMI does not wake up. There are some individual signs of life, like the interior lights turning on, sunroof and windows being functional, etc.

VCDS reveals "Cannot be reached" on a good number of modules. I've beeped all of the fuses with a multimeter (trunk, both sides of dash, under engine ECU), none seem blown. I also tried clearing all codes, just to see what would happen. Despite looking searching online for answers, I'm not quite sure how to proceed.



Any ideas?




Full VCDS log. I've got some saved logs from before clearing codes saved as well:

Chassis Type: 4G-AU57 (4G0)
Scan: 01 02 03 05 08 09 10 15 16 17 19 3B 42 44 46 47 52 53 55 5F
62 6C 6D 72 AC

VIN: WAUZZZ4G2EN208137 Mileage: 306892km-190693miles

01-Engine -- Status: OK 0000
02-Auto Trans -- Status: Malfunction 0010
03-ABS Brakes -- Status: Malfunction 0110
04-Steering Angle -- Status: Cannot be reached 0100
05-Acc/Start Auth. -- Status: Malfunction 0010
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: OK 0000
10-Park/Steer Assist -- Status: Cannot be reached 0100
15-Airbags -- Status: Cannot be reached 0100
16-Steering wheel -- Status: OK 0000
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: OK 0000
3B-Sensor Elect. -- Status: Malfunction 0010
42-Door Elect, Driver -- Status: OK 0000
44-Steering Assist -- Status: Malfunction 0010
46-Central Conv. -- Status: Malfunction 0010
47-Sound System -- Status: Cannot be reached 0100
52-Door Elect, Pass. -- Status: OK 0000
53-Parking Brake -- Status: OK 0000
55-Headlight Range -- Status: Cannot be reached 0100
5F-Information Electr. -- Status: Cannot be reached 0100
62-Door, Rear Left -- Status: OK 0000
6C-Back-up Cam. -- Status: OK 0000
6D-Trunk Elect. -- Status: Malfunction 0010
72-Door, Rear Right -- Status: OK 0000
AC-Reductant Control -- Status: OK 0000

-------------------------------------------------------------------------------
Address 01: Engine (J623-CNHA) Labels:. 04L-907-309-V1.clb
Part No SW: 04L 906 021 BD HW: 04L 907 309
Component: R4 2,0L EDC H23 8244
Revision: 85H23--- CVN: 4E6FCE802AA4345400000000
Coding: 12254012242401080000
Shop #: WSC 65535 000 00000
ASAM Dataset: EV_ECM20TDI01104L906021BD 002005
ROD: EV_ECM20TDI01104L906021BD_002.rod
VCID: 68DF0DA79373D2D363-803C
VINID: 9D196AAAA1170957820080431CD00E6510

No fault code found.
Readiness: 0 0 0 0 1

-------------------------------------------------------------------------------
Address 02: Auto Trans (J217) Labels:| 0CJ-927-156.clb
Part No SW: 4G0 927 153 Q HW: 0CK 927 156 Q
Component: 0CK 20TDI RdW H01 0002
Revision: --H01--- Serial number: 0000000075
Coding: 000001
Shop #: WSC 02391 785 00200
ASAM Dataset: EV_TCMDL382021 002014
ROD: EV_TCMDL382021_AU57.rod
VCID: 377D9EDB8E4D8D2B3A-8062

7 Faults Found:
20788 - Gate Select Position Circuit for Tiptronic (F189)
P0904 00 [038] - Electrical Malfunction
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 4
Fault Frequency: 1
Mileage: 306892 km
Date: 2024.02.25
Time: 00:11:50

Engine RPM: 0 /min
Driving position: P
ATF temperature: 33 C
Transmission output speed: 0 /min
Voltage terminal 30: 12.1 V
Engine torque: 0 Nm
selected gear: 1
Ctrl. mod.: operating condition: regular operation
Auxiliary pump for transmission: requesting function: Preloading
Auxiliary hydraulic pump for transmission oil: current: 0 A
Oil pressure reservoir: pressure: 18.2 bar
Pressure of clutch 1: actual value: 0.0 bar
Pressure of clutch 2: actual value: 0.0 bar
Clutch status: Neutral
Unlearning counter according OBD: 40
Occurrence_counter_over_length_of_life: 5

20790 - Gear Shift Lock Solenoid Control Circuit
P0930 00 [038] - Low
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 4
Fault Frequency: 1
Mileage: 306892 km
Date: 2024.02.25
Time: 00:11:50

Engine RPM: 0 /min
Driving position: P
ATF temperature: 33 C
Transmission output speed: 0 /min
Voltage terminal 30: 12.1 V
Engine torque: 0 Nm
selected gear: 1
Ctrl. mod.: operating condition: regular operation
Auxiliary pump for transmission: requesting function: Preloading
Auxiliary hydraulic pump for transmission oil: current: 0 A
Oil pressure reservoir: pressure: 18.2 bar
Pressure of clutch 1: actual value: 0.0 bar
Pressure of clutch 2: actual value: 0.0 bar
Clutch status: Neutral
Unlearning counter according OBD: 40
Occurrence_counter_over_length_of_life: 4

20921 - Terminal 15
U1405 00 [038] - Implausible signal
[New feature! Extended UDS fault detail is only supported by current gen. interfaces]
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 4
Fault Frequency: 1
Mileage: 306892 km
Date: 2024.02.25
Time: 00:11:50

Engine RPM: 0 /min
Driving position: P
ATF temperature: 33 C
Transmission output speed: 0 /min
Voltage terminal 30: 12.1 V
Engine torque: 0 Nm
selected gear: 1
Ctrl. mod.: operating condition: regular operation
Auxiliary pump for transmission: requesting function: Preloading
Auxiliary hydraulic pump for transmission oil: current: 0 A
Oil pressure reservoir: pressure: 18.2 bar
Pressure of clutch 1: actual value: 0.0 bar
Pressure of clutch 2: actual value: 0.0 bar
Clutch status: Neutral
Unlearning counter according OBD: 40
Occurrence_counter_over_length_of_life: 2

20931 - No Communication with Instrument Cluster
U0155 00 [038] - -
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 6
Fault Frequency: 3
Mileage: 306892 km
Date: 2024.02.25
Time: 00:09:02

Engine RPM: 0 /min
Driving position: P
ATF temperature: 34 C
Transmission output speed: 0 /min
Voltage terminal 30: 12.1 V
Engine torque: 0 Nm
selected gear: N
Ctrl. mod.: operating condition: regular operation
Auxiliary pump for transmission: requesting function: Fill hydraulic press. accum.
Auxiliary hydraulic pump for transmission oil: current: 2 A
Oil pressure reservoir: pressure: 15.6 bar
Pressure of clutch 1: actual value: 0.0 bar
Pressure of clutch 2: actual value: 0.0 bar
Clutch status: New
Unlearning counter according OBD: 40
Occurrence_counter_over_length_of_life: 4

20936 - No Communications with Steering Angle Sender (G85)
U0126 00 [038] - -
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 6
Fault Frequency: 8
Mileage: 306892 km
Date: 2024.02.25
Time: 00:02:05

Engine RPM: 0 /min
Driving position: P
ATF temperature: 34 C
Transmission output speed: 0 /min
Voltage terminal 30: 12.3 V
Engine torque: 0 Nm
selected gear: 1
Ctrl. mod.: operating condition: regular operation
Auxiliary pump for transmission: requesting function: Preloading
Auxiliary hydraulic pump for transmission oil: current: 0 A
Oil pressure reservoir: pressure: 18.7 bar
Pressure of clutch 1: actual value: 0.0 bar
Pressure of clutch 2: actual value: 0.0 bar
Clutch status: Neutral
Unlearning counter according OBD: 40
Occurrence_counter_over_length_of_life: 9

20940 - Steering Column Control Module
U0212 00 [038] - No Communications
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 6
Fault Frequency: 1
Mileage: 306892 km
Date: 2024.02.25
Time: 00:06:08

Engine RPM: 0 /min
Driving position: P
ATF temperature: 34 C
Transmission output speed: 0 /min
Voltage terminal 30: 12.2 V
Engine torque: 0 Nm
selected gear: 1
Ctrl. mod.: operating condition: regular operation
Auxiliary pump for transmission: requesting function: No function active
Auxiliary hydraulic pump for transmission oil: current: 0 A
Oil pressure reservoir: pressure: 27.9 bar
Pressure of clutch 1: actual value: 0.0 bar
Pressure of clutch 2: actual value: 0.0 bar
Clutch status: Neutral
Unlearning counter according OBD: 40
Occurrence_counter_over_length_of_life: 1

20944 - Implausible Data Received from Engine Control Module
U0401 00 [038] - -
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 6
Fault Frequency: 1
Mileage: 306892 km
Date: 2024.02.25
Time: 00:11:50

Engine RPM: 0 /min
Driving position: P
ATF temperature: 33 C
Transmission output speed: 0 /min
Voltage terminal 30: 12.1 V
Engine torque: 0 Nm
selected gear: 1
Ctrl. mod.: operating condition: regular operation
Auxiliary pump for transmission: requesting function: Preloading
Auxiliary hydraulic pump for transmission oil: current: 0 A
Oil pressure reservoir: pressure: 18.2 bar
Pressure of clutch 1: actual value: 0.0 bar
Pressure of clutch 2: actual value: 0.0 bar
Clutch status: Neutral
Unlearning counter according OBD: 40
Occurrence_counter_over_length_of_life: 14


-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels:. 4G0-907-379-V1.clb
Part No SW: 4G0 907 379 L HW: 4G0 907 379 L
Shop #: WSC 02391 785 00200
ASAM Dataset: EV_ESPPremiAU57X 004039
ROD: EV_ESPPremiAU57X_004_AU57.rod
VCID: 3A7B87EFBD5F9043C5-806E

No fault code found.

-------------------------------------------------------------------------------
Address 05: Acc/Start Auth.
Cannot be reached

-------------------------------------------------------------------------------
Address 08: Auto HVAC (J255) Labels:| 4G0-820-043-2Z.clb
Part No SW: 4G0 820 043 BA HW: 4G0 820 043 BA
Component: KLIMA 2 ZONEN H14 0096
Serial number: 15101400110853
Coding: 3422090829
Shop #: WSC 02391 785 00200
ASAM Dataset: EV_AirCondiBasisUDS 004002
ROD: EV_AirCondiBasisUDS_004.rod
VCID: 5FCD167B463D956B92-800A

No fault code found.

-------------------------------------------------------------------------------
Address 09: Cent. Elect. (J519) Labels:. 4H0-907-063-V1.clb
Part No SW: 4H0 907 063 CE HW: 4H0 907 063 E
Component: BCM1 2.0 H12 0130
Revision: 19012002 Serial number: 00000001815245
Coding: 2600A01140349FE00981008400001D0C0F9DC7082709020100 0004606900
Shop #: WSC 02391 785 00200
VCID: 6DD17CB3B491F7FB10-8038

Subsystem 1 - Part No SW: 4G2 955 119 HW: 4G8 955 119 A Labels: 1KX-955-119.CLB
Component: WWS57X 140919 H37 0080
Serial number: 141008203324
Coding: 0045F7

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: 23406070
Coding: 02006D

Subsystem 3 - Part No SW: 4G0 941 531 BE HW: 4G0 941 531 BE
Component: E1 - LDS H07 0044
Serial number: 04 11 2014 00000550

No fault code found.

-------------------------------------------------------------------------------
Address 10: Park/Steer Assist
Cannot be reached

-------------------------------------------------------------------------------
Address 15: Airbags
Cannot be reached

-------------------------------------------------------------------------------
Address 16: Steering wheel (J527) Labels:. 4H0-953-568.clb
Part No SW: 4G0 953 568 A HW: 4G0 953 568 A
Component: Lenks.Modul H05 0201
Revision: 00000000 Serial number: 20141105000155
Coding: 000035
Shop #: WSC 02391 785 00200
VCID: 306FA5C763235A137B-8064

Subsystem 1 - Part No SW: 4G0 951 528 A HW: 4G0 951 528 A
Component: E221 - MFL H08 0010

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments (J285) Labels:| 4H0-920-xxx-17.clb-SRI1
Part No SW: 4G8 920 950 S HW: 4G8 920 950 S
Component: MDieGb H43 0411
Revision: 27450259 Serial number: 658281014592063
Coding: 23A712000B412600010000
Shop #: WSC 02391 785 00200
ASAM Dataset: EV_RBC7KMID 004048
ROD: EV_RBC7KMID.rod
VCID: 3F8DF6FBA67DB56BF2-806A

No fault code found.

-------------------------------------------------------------------------------
Address 19: CAN Gateway (J533) Labels:| 4H0-907-468.clb
Part No SW: 4G0 907 468 AD HW: 4G0 907 468 AC
Component: J533--Gateway H13 0050
Revision: -------- Serial number: 00000001620236 Dataset Number: 4G0909515H 0067
Coding: 00CD074400
Shop #: WSC 02391 785 00200
GVL: FDA1C800FC6360030000
ASAM Dataset: EV_GatewPkoUDS 001019
ROD: EV_GatewPkoUDS_001_AU57.rod
VCID: 72EB6FCFA5AF2803CD-8026

Battery Monitoring Control Module:
Subsystem 1 - Part No SW: 8T0 915 181 HW: 8T0 915 181
Component: J367-BDMHella H03 8041
Serial number: 2809194503

Voltage stabilizer:
Subsystem 2 - Part No SW: 8K0 959 663 F HW: 8K0 959 663
Component: J532_DCDCStab H23 0021
Serial number: 140729000000000002FF

1 Fault Found:
0267 - Optical data bus
U1049 00 [009] - Open circuit
Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Reset counter: 68
Mileage: 306892 km
Date: 2024.02.25
Time: 00:39:58

Voltage terminal 30: 13.5 V
Voltage terminal 15: 0.0 V
Control Module temperature: 26 C
System status: Awake_Timer_active
IN ESP_standstill flag: standstill detected
Engine running: OFF
IN ZAS_Te_X: OFF
Terminal 15 status via CAN: OFF
Terminal 15 status: OFF
Datenfeld: 0


-------------------------------------------------------------------------------
Address 3B: Sensor Elect. (J849) Labels: 4G0-907-637.clb
Part No SW: 4G0 907 637 H HW: 4G0 907 637 D
Component: SARA 3D H04 0056
Revision: -------- Serial number: EJ1BPA720DE0WJ Dataset Number: 4G0909573C 0006
Shop #: WSC 00000 000 00000
ASAM Dataset: EV_SARA2 005012
ROD: EV_SARA2.rod
VCID: 3365AACB9A35610B06-8066

1 Fault Found:
3801346 - Databus
U1121 00 [008] - Missing Message
[New feature! Extended UDS fault detail is only supported by current gen. interfaces]
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 6
Fault Frequency: 2
Reset counter: 108
Mileage: 306892 km
Date: 2024.02.25
Time: 00:11:27

DCU_Internal_DTC: 3A 01 02
Ignition Cycle Count: 48283
DCU Temperature: 21 C
Voltage terminal 30: 13.2 V
Voltage VBG 22: 2.5 V
VIN received: 00000000000000000
Debug Data: 00 00 00 00 00 00 00 00


-------------------------------------------------------------------------------
Address 42: Door Elect, Driver
Cannot be reached

-------------------------------------------------------------------------------
Address 44: Steering Assist (J500) Labels:| 4G0-909-144.clb
Part No SW: 4G0 909 144 M HW: 4G0 909 144 G
Component: RCEPS H41 0011
Revision: 00001000 Serial number: 0012090691 Dataset Number: 4G0909852M 0031
Coding: 101000010000
Shop #: WSC 02391 785 00200
ASAM Dataset: EV_RCEPS 009010
ROD: EV_RCEPS_009.rod
VCID: 3365AACB9A35610B06-8066

2 Faults Found:
3158276 - Function Restricted due to Missing Message(s)
U1111 00 [008] - -
[New feature! Extended UDS fault detail is only supported by current gen. interfaces]
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 6
Fault Frequency: 8
Reset counter: 108
Mileage: 306892 km
Date: 2024.02.25
Time: 00:02:05

Write only channel

15888 - Terminal 15
U1405 00 [008] - Implausible signal
[New feature! Extended UDS fault detail is only supported by current gen. interfaces]
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 2
Reset counter: 108
Mileage: 306892 km
Date: 2024.02.25
Time: 00:02:36

Write only channel


-------------------------------------------------------------------------------
Address 46: Central Conv.
Cannot be reached

-------------------------------------------------------------------------------
Address 47: Sound System
Cannot be reached

-------------------------------------------------------------------------------
Address 52: Door Elect, Pass.
Cannot be reached

-------------------------------------------------------------------------------
Address 53: Parking Brake (----) Labels: 4H0-907-801.clb
Part No SW: 4H0 907 801 H HW: 4H0 907 801 A
Component: EPB-4 H04 0015
Revision: -------- Serial number: 00000001254820 Dataset Number: 4G0909522D 0007
ASAM Dataset: EV_ParkiBrake 001028
ROD: EV_ParkiBrake_VW51.rod
VCID: 2D51BCB37C1137FB50-8078

No fault code found.

-------------------------------------------------------------------------------
Address 55: Headlight Range
Cannot be reached

-------------------------------------------------------------------------------
Address 5F: Information Electr.
Cannot be reached

-------------------------------------------------------------------------------
Address 62: Door, Rear Left
Cannot be reached

-------------------------------------------------------------------------------
Address 6C: Back-up Cam.
Cannot be reached

-------------------------------------------------------------------------------
Address 6D: Trunk Elect. (----) Labels:* Redir Fail!
Part No SW: 4G9 959 107 B HW: 4G9 959 107 A
Component: HDSG-Modul H03 0143
Revision: 14003001 Serial number: 292400963 Dataset Number: 4G0909541D 0027
Coding: 097205C010
Shop #: WSC 02391 785 00200
ASAM Dataset: EV_HDSGAu572 001022
ROD: EV_HDSGAu571.rod
VCID: 356194D394417F3B28-8060

1 Fault Found:
0114 - Load Space Cover
B12EF 54 [137] - Missing Calibration / Basic Setting
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Reset counter: 68
Mileage: 306892 km
Date: 2024.02.25
Time: 00:43:38

Voltage terminal 30: 12.03 V


-------------------------------------------------------------------------------
Address 72: Door, Rear Right
Cannot be reached

-------------------------------------------------------------------------------
Address AC: Reductant Control (J880) Labels: 4G0-907-355.clb
Part No SW: 4G0 907 355 C HW: 4G0 907 355 B
Component: SCR-Stg-G2 H10 0010
Revision: 00000000 Serial number: 142930031 Dataset Number: 4G0909571H 0017
ASAM Dataset: EV_RDCMA00100 008040
ROD: EV_RDCMA00100.rod
VCID: 2B55B2AB420539CB4E-807E

No fault code found.

End-------------------------(Elapsed Time: 04:16)--------------------------

[Craftingcat99]

I just faced a relatively similar issue on my A4 B8, I don't know much about the A6 family, but make sure no water got into any of your convenience CAN system. For me it was a leaking sunroof that flooded all the computers in the right trunk space. Again I'm definitely not a professional at all, it just seems to be a relatively quick thing to check all the lowest spaces under any of the a/b/c pillars for any water. Hope you find the cause of this issue.

Sent from my SM-G986B using Tapatalk

[its_tcs]

Thank for your reply, Craftingcat99


I haven't found any water ingress around the car so far, but I will have a closer look at the low spots, and the module stack in the trunk. It is a sunroof car..

Did you need to replace any modules on your B8 in the end?

[Craftingcat99]

Thank for your reply, Craftingcat99


I haven't found any water ingress around the car so far, but I will have a closer look at the low spots, and the module stack in the trunk. It is a sunroof car..

Did you need to replace any modules on your B8 in the end?Yeah, sadly, I'm in the middle of replacing the damaged components. I have to bring it to an authorized Audi dealership, because they have to replace the Comfort control module (BCM2) and also the trailer recognition module. Sadly the BCM2 is the Immobilizer master and only Audi can program anything regarding the Immobilizer... I hope they don't find any other broken modules.

Sent from my SM-G986B using Tapatalk

[Shane Horning]

Could be the ignition immobilizer thing. It's under the steering wheel

Sent from my SM-S921U using Audizine Forum mobile app (http://r.tapatalk.com/byo?rid=87676)

[MyDimeIsUp]

Bad ground or something related to the CAN gateway possibly?

[its_tcs]

Thanks everyone, some progress


As I said, the car unlocks with the keyfob, but nothing else. When I now keep holding the unlock button on the key while pressing the start/stop button in the car, "key not recognised" flashes on the dash. It doesn't help to hold the key against the designated area as the message prescribes, however.


My second key didn't have a battery in it, and I removed the one from the other key to check which type I needed to get.

Do the keys need to be resynced after being without power?
Is there a super secret syncing procedure?


https://ibb.co/Jz2vJtF

[Shane Horning]

If you don't have any blown fuses, pull the steering column apart and check the wiring at the immobilizer. I've seen a broken wire there on a b8.5. If all is well I'm gonna say replace the immobilizer

Sent from my SM-S921U using Audizine Forum mobile app (http://r.tapatalk.com/byo?rid=87676)

[Alabama]

The ignition does not turn on anymore. After getting in (central locking still works) the A6 screen flashes on the the dash, but after that nothing. No response to the start/stop button, MMI does not wake up. There are some individual signs of life, like the interior lights turning on, sunroof and windows being functional, etc. VCDS reveals "Cannot be reached" on a good number of modules. I've beeped all of the fuses with a multimeter (trunk, both sides of dash, under engine ECU), none seem blown. I also tried clearing all codes, just to see what would happen. Despite looking searching online for answers, I'm not quite sure how to proceed. Any ideas?

Weird. In the summary Module 19 supposedly has no faults, but in the details Module 19 has a fault, and Voltage Terminal 15 reads 0.0V. Also, all the dates are back in February. Odd that all this happened at once without any other change. We had one AZ member who developed many faults after someone reversed the positive and negative leads when installing a new battery. Any other information to help the smart folk here?

[its_tcs]

If you don't have any blown fuses, pull the steering column apart and check the wiring at the immobilizer. I've seen a broken wire there on a b8.5. If all is well I'm gonna say replace the immobilizer

Sent from my SM-S921U using Audizine Forum mobile app (http://r.tapatalk.com/byo?rid=87676)


I'll have a look at the immobilizer as soon as I get some time on my hands. check it for power and ground at least.

[its_tcs]

Weird. In the summary Module 19 supposedly has no faults, but in the details Module 19 has a fault, and Voltage Terminal 15 reads 0.0V. Also, all the dates are back in February. Odd that all this happened at once without any other change. We had one AZ member who developed many faults after someone reversed the positive and negative leads when installing a new battery. Any other information to help the smart folk here?



The February thing can be explained by the battery being completely dead when I bought the car. I never reset the date.

It's a bit of a mystery car, bought it at a repossession auction with part history present. According to the description, the battery was dead and the car had a stutter when revved. This stutter soon turned into something much worse, with me getting stranded on the side of the road in a big cloud of diesel smoke. I tried to diagnose it on the spot, using jump leads to another car for power (I know, I know..), but ended up trailering it home.

At home, I found out that one of the injectors was fully stuck open. Upon having all 4 tested, 2 were stuck open, and the other 2 where overfueling badly as well. Interestingly, 2 injectors where the correct type for my engine code, 2 weren't. A set of refurb injectors did the trick, however, and I drove the car about 60 miles without issue.


Then, the reason for posting on AZ started..


As I said a few posts prior:

The car unlocks with the keyfob, but nothing else. When I now keep holding the unlock button on the key while pressing the start/stop button in the car, "key not recognised" flashes on the dash. It doesn't help to hold the key against the designated area as the message prescribes, however.


My second key didn't have a battery in it, and I removed the one from the other key to check which type I needed to get.

Do the keys need to be resynced after being without power?
Is there a super secret syncing procedure?


This would explain why I can't communicate with half of the modules, and might be the immobiliser like Shane suggests. It seems very similar to the steering lock issue common with the C6 A6's



TLDR on what happened on the electrical side:

- battery completely dead
- replaced battery, coded in
- replaced injectors, coded in
- had battery out of both keyfobs
- keys don't seem to be recognized anymore

[Trademark2k6]

Hey

I have a similar issue and was wondering if you managed to solve?

Today I drove the car and all of a sudden I get a message saying stop/start system malfunction, take to workshop. And it had a yellow triangle wanting light. It still drove okay.

Then I parked it and turned the car off. And since then it won’t turn on. Like you, the car unlocks with the fob. The dash has power. But the start/stop button does nothing and therefore no ignition.

I removed battery for an hour. Reconnected. And still nothing.

Was told it might be the 645 multifunction relay under the bonnet. I changed this (although it wasn’t a VW one but a generic one with 4 pins and same wiring diagram on it, and also 40 amp). This still did nothing.

Haven’t plugged into vagcom yet as I thought it won’t work as there is no ignition. But it seem it might still be worth a try?

Any help is appreciated!

Also I also noticed the brief “key not recognised” while I was pressing the start button and messing with the fob. Putting it against the dash didn’t help.

I have a spare key. And that didn’t help either.

[Trademark2k6]

Oh sorry to add - I also attached jump leads from a friends car onto mine (via the battery in boot). That didn’t help!