EPB fault and parking brake not working after rear brake pad change

[c6enthusiast]

To preface, i bought a 2008 4.2 a6 on auction with 40k miles. It had been sitting for a considerably long time- around 2 years before it got to me so the rotors were caked in rust/dust, and I decided to do the brakes after repairing the front end damage. While doing this, I had made an extremely stupid and ignorant mistake, a few of them actually. First, I did not have the battery connected to the charger, for it was a brand new battery and I thought I could do the job quick enough to where it wouldn't be a problem (first mistake.) Second, I was having trouble retracting one of the pistons, so I had thought that I did not fully open them through vcds. Being as stupid as I am, i went and attempted to open them again through vcds, and obviously nothing happened. Once the job was done, I went to close the epb, and nothing happened. Functioned showed 0 amps going to either motor. I waited frustratingly for a couple hours until it miraculously decided to work after hooking it up to a charger, and the brakes closed. I then attempted to cycle the parking brake through the switch, and the red "park brake" light just flashes on the dash, along with the parking brake malfunction error. I did a parking brake function test through vcds, and they did indeed work this time. I was also able to open/ close them thru vcds with no issue. I also find it important to note that when I go to advanced measuring values, and select operating button, it simply shows ERROR. Perhaps the switch needs replacement? Do i check power/ signal to the switch? The following error codes persisted: Monday,31,March,2025,09:32:46:39010
VCDS Version: Release 25.3.0 (x64) Running on Windows 11 x64
www.Ross-Tech.com

Address 53: Parking Brake Labels: 4F0-910-801.clb
Control Module Part Number: 4F0 910 801 C HW: 4F0 907 801 A
Component and/or Version: EPB CDEC0080 H04 0080
Software Coding: 0007022
Work Shop Code: WSC 02324 758 00200
VCID: 20128C2C17CA652AAF7-8074
Fault Codes have been Erased

2 Faults Found:
02442 - Function Lamp in Control Head
009 - Open or Short to Ground
Freeze Frame:
Fault Status: 01101001
Fault Priority: 6
Fault Frequency: 4
Reset counter: 71
Mileage: 69320 km
Time Indication: 0
Date: 2025.03.31
Time: 08:55:40

Freeze Frame:
Voltage: 11.08 V
Count: 65

02443 - Control Head
012 - Electrical Fault in Circuit - MIL ON
Freeze Frame:
Fault Status: 11101100
Fault Priority: 2
Fault Frequency: 8
Reset counter: 57
Time Indication: 0

Freeze Frame:
Voltage: 7.45 V
Count: 40

I checked the fuse for the electronic parking brake, and it does not appear to be popped, and it is receiving 14.13 volts with ignition on. I have a donor car of the same spec/ year, so I decided to replace the epb module and they have the same part number. The issue persists and I still get the same error codes, parking brake still does not function. Any idea what my next step should be? Below is the full scan of the vehicle:Friday,28,March,2025,20:23:33:39010
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 11 x64
VCDS Version: 25.3.0.4 (x64) HEX-NET2 CB: 0.4660.5
Data version: 20250311 DS365.0
www.Ross-Tech.com


VIN: WAUDV74F88N138388 License Plate: 32VA6.1
Mileage: 69320km-43073mi Repair Order:



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


Chassis Type: 4F (4L0)
Scan: 01 02 03 05 07 08 09 0E 0F 15 16 17 19 1E 36 37 42 46 47 4F
52 53 55 56 61 62 65 67 6C 72 76 77

VIN: WAUDV74F88N138388 Mileage: 69320km-43073miles

00-Steering Angle Sensor -- Status: OK 0000
01-Engine -- Status: Malfunction 0010
02-Auto Trans -- Status: OK 0000
03-ABS Brakes -- Status: Malfunction 0010
05-Acc/Start Auth. -- Status: OK 0000
07-Control Head -- Status: OK 0000
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: Malfunction 0010
0E-Media Player 1 -- Status: OK 0000
0F-Digital Radio -- Status: Malfunction 0010
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: OK 0000
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: OK 0000
1E-Media Player 2 -- Status: OK 0000
36-Seat Mem. Drvr -- Status: OK 0000
37-Navigation -- Status: OK 0000
42-Door Elect, Driver -- Status: OK 0000
46-Central Conv. -- Status: Malfunction 0010
47-Sound System -- Status: OK 0000
4F-Centr. Electr. II -- Status: OK 0000
52-Door Elect, Pass. -- Status: OK 0000
53-Parking Brake -- Status: Malfunction 0010
55-Headlight Range -- Status: Malfunction 0010
56-Radio -- Status: OK 0000
61-Battery Regul. -- Status: OK 0000
62-Door, Rear Left -- Status: OK 0000
65-Tire Pressure -- Status: OK 0000
67-Voice Control -- Status: OK 0000
6C-Back-up Cam. -- Status: OK 0000
72-Door, Rear Right -- Status: OK 0000
76-Park Assist -- Status: OK 0000
77-Telephone -- Status: OK 0000
-------------------------------------------------------------------------------
Address 01: Engine Labels:. 079-907-560-BVJ.clb
Part No SW: 4F1 910 560 E HW: 4F1 907 560
Component: 4.2l V8/4V 0030
Revision: 74H05--- Serial number:
Coding: 01050009190F0120
Shop #: WSC 02335 785 00200
VCID: 251C9D3809E88002DC1-8070
VINID: 9D19549871162087810C80C820061F7E87

2 Faults Found:
005715 - Please check DTC Memory of ABS Controller
P1653 - 008 - - Intermittent
Freeze Frame:
Fault Status: 00101000
Fault Priority: 2
Fault Frequency: 2
Reset counter: 255
Mileage: 69226 km
Time Indication: 0
Date: 2007.05.18
Time: 07:29:59

Freeze Frame:
RPM: 619 /min
Load: 18.0 %
Speed: 0.0 km/h
Temperature: 82.0 C
Temperature: 21.0 C
Absolute Pres.: 980.0 mbar
Voltage: 14.605 V

000818 - Knock Sensor 2 (G66)
P0332 - 002 - Signal too Low
Freeze Frame:
Fault Status: 01100010
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 69227 km
Time Indication: 0
Date: 2007.05.18
Time: 08:06:52

Freeze Frame:
RPM: 2051 /min
Load: 38.8 %
Speed: 16.0 km/h
Temperature: 99.0 C
Temperature: 39.0 C
Absolute Pres.: 980.0 mbar
Voltage: 14.478 V

Readiness: 0000 0000

-------------------------------------------------------------------------------
Address 02: Auto Trans Labels: 09L-927-760.lbl
Part No SW: 4F5 910 156 A HW: 09L 927 156 C
Component: AG6 09L 4,2 FSI USA 0010
Revision: --H04--- Serial number: 4443701
Coding: 0000002
Shop #: WSC 02325 785 00200
VCID: 261E9A3474EE8B1AD5B-8072

No fault code found.

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 4F0-910-517.clb
Part No SW: 4F0 910 517 AD HW: 4F0 614 517 AA
Component: ESP8 quattro H01 0070
Revision: 00000000 Serial number: 00000000000000
Coding: 0020840
Shop #: WSC 02325 785 00200
VCID: 669EDA34B46E4B1A15B-8032

1 Fault Found:
00473 - Control Module for Elect. Park/Hand Brake (J540)
013 - Check DTC Memory
Freeze Frame:
Fault Status: 01101101
Fault Priority: 3
Fault Frequency: 1
Reset counter: 69
Mileage: 69323 km
Time Indication: 0
Date: 2025.03.28
Time: 20:00:21

Freeze Frame:
Hex Value: 0x00C0
Hex Value: 0x4082
Hex Value: 0x0035
Hex Value: 0x01AF
Hex Value: 0x00FF


-------------------------------------------------------------------------------
Address 05: Acc/Start Auth. Labels:. 4F0-910-852.clb
Part No SW: 4F0 910 852 A HW: 4F0 905 852 C
Component: FBSAUDIC6 ELVSG H01 0040
Revision: 09010701 Serial number: 10601601042430
Coding: 0000007
Shop #: WSC 15959 006 1048576
VCID: 241A803C02D2790ACBF-8070

Subsystem 1 - Part No: 4F0 910 131 L
Component: FBSAUDIC6 EZS H46 0080

Subsystem 2 - Part No: 4F0 910 335
Component: FBSAUDIC6 KSG H27 0080

Subsystem 3 - Part No: 4F0 910 220 G
Component: FBSAUDIC6 IDG H01 0060

No fault code found.

-------------------------------------------------------------------------------
Address 07: Control Head Labels: 4F0-910-7xx-07-H.clb
Part No SW: 4F0 910 732 D HW: 4E0 035 729 A
Component: Interfacebox H43 4140
Revision: 00000000 Serial number: 361DI087521522
Coding: 0000003
Shop #: WSC 02335 785 00200
VCID: 241A803C02D2790ACBF-8070

Subsystem 1 - Part No: 4F0 910 609 E
Component: Bedienteil MMIC6H01 0060

Subsystem 2 - Serial number: 00000001040129

Subsystem 3 - Serial number: 0102.04.080000000100011191

Subsystem 4 - Serial number: 011191

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 4F0-910-043.clb
Part No SW: 4F0 910 043 A HW: 4F1 820 043 AG
Component: KLIMABETAETIGUNGH30 0020
Revision: 00000053 Serial number: 00000000515935
Coding: 0524328
Shop #: WSC 02325 785 00200
VCID: 1C6AB8DC3AA241CA73F-8048

No fault code found.

-------------------------------------------------------------------------------
Address 09: Cent. Elect. Labels: 4F0-910-279.lbl
Part No SW: 4F0 910 279 J HW: 4F0 907 279 A
Component: ILM Fahrer H18 0250
Revision: 00000000 Serial number: 4F0907279
Coding: 0113123
Shop #: WSC 02335 785 00200
VCID: 30327C6C462AD5AA3F7-8064

Subsystem 1 - Part No: 4F1 910 113 C Labels: 1KX-955-119.CLB
Component: Wischer AudiC6 H06 0210
Coding: 00064784
Shop #: WSC 02335

Subsystem 2 - Part No: 4E0 910 557 B Labels: 8K0-955-559.CLB
Component: REGENLICHTSENSORH13 0100
Coding: 00146221
Shop #: WSC 02335

2 Faults Found:
01494 - Bulb for Parking Lamps; Left (M1)
011 - Open Circuit
Freeze Frame:
Fault Status: 01101011
Fault Priority: 2
Fault Frequency: 1
Reset counter: 70
Mileage: 69320 km
Time Indication: 0
Date: 2025.03.28
Time: 20:01:00

01498 - Bulb for Parking Lamps; Right (M3)
011 - Open Circuit
Freeze Frame:
Fault Status: 01101011
Fault Priority: 2
Fault Frequency: 1
Reset counter: 70
Mileage: 69320 km
Time Indication: 0
Date: 2025.03.28
Time: 20:01:00


-------------------------------------------------------------------------------
Address 0E: Media Player 1 (R192) Labels:. 4E0-035-785.lbl
Part No SW: 4E0 035 785 B HW: 4E0 035 785 B
Component: SG ext.Player H15 0700
Revision: 00000000
VCID: 270097307FE49212EED-8072

No fault code found.

-------------------------------------------------------------------------------
Address 0F: Digital Radio Labels: 4E0-910-593-SIR.lbl
Part No SW: 4E0 910 593 K HW: 4E0 035 593 F
Component: SDAR SIRIUS H07 0140
Revision: 00000000 Serial number: AUZ4Z7H0307359
Coding: 0000100
Shop #: WSC 00000 000 00000
VCID: 2F307F105B14CA5226D-807A

1 Fault Found:
02635 - Tuner Not Enabled/Activated
000 - -
Freeze Frame:
Fault Status: 01100000
Fault Priority: 7
Fault Frequency: 1
Reset counter: 69
Mileage: 69323 km
Time Indication: 0
Date: 2025.03.28
Time: 19:58:53


-------------------------------------------------------------------------------
Address 15: Airbags Labels: 4F0-910-655-8R.clb
Part No SW: 4F0 910 655 F HW: 4F0 959 655 A
Component: 6N AIRBAG AUDI8RH30 0300
Revision: 15H30000 Serial number: 00359D0GF1P1
Coding: 0013902
Shop #: WSC 02325 785 00200
VCID: 2A066E0460F6AF7AF13-807E

Subsystem 1 - Part No: 4F0 910 339 B
Component: BF-Gewichtsens. H03 0060

Subsystem 2 - Serial number: 6332CSME38516E57A

Subsystem 3 - Serial number: 6342CSME39062613Z

Subsystem 4 - Serial number: 6352QSME5A741607H

Subsystem 5 - Serial number: 6362QSME5F427811L

Subsystem 6 - Serial number: 63734SME370E3C197

Subsystem 7 - Serial number: 63834SME354C4A7DH

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel Labels: 4F0-910-549.lbl
Part No SW: 4F0 910 549 A HW: 4F0 953 549 D
Component: J0527 0410
Revision: 00H03000 Serial number: 90055080880032
Coding: 0012041
Shop #: WSC 02323 785 00200
VCID: 2700973073E49212EED-8072

Subsystem 1 - Part No: XXXXXXXXXXX
Component: E0221 H02 0030

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 4F0-920-KOM-V1.clb
Part No SW: 4F0 910 930 C HW: 4F0 920 983
Component: KOMBIINSTR. M73 H23 0240
Revision: 00000000 Serial number: 72X31M748
Coding: 2129288
Shop #: WSC 11662 004 1048576
VCID: 2318832007DC7E32B25-8076

No fault code found.

-------------------------------------------------------------------------------
Address 19: CAN Gateway Labels:. 4L0-910-468.clb
Part No SW: 4L0 910 468 A HW: 4L0 907 468 B
Component: J533__Gateway H06 0060
Revision: 00H06000 Serial number: 1100B084050071
Coding: F5D5DE77707A0600
Shop #: WSC 02335 785 00200
VCID: 2D0C65185118B842141-8078

No fault code found.

-------------------------------------------------------------------------------
Address 1E: Media Player 2 Labels: 4E0-910-111.lbl
Part No SW: 4E0 910 110 C HW: 4E0 035 110 A
Component: MP3-Changer H46 0350
Revision: 00046007 Serial number: AUZ5ZBH8370419
Shop #: WSC 00000 000 00000
VCID: 1862A4CCCE9A2DEA577-804C

No fault code found.

-------------------------------------------------------------------------------
Address 36: Seat Mem. Drvr Labels: None
Part No SW: 4F0 910 760 HW: 4F0 959 760
Component: Sitzmemory FS H04 0050
Revision: 00000000 Serial number: 00000000896400
Coding: 0082954
Shop #: WSC 02335 785 00200
VCID: 6194C9285D402C22E09-8034

No fault code found.

-------------------------------------------------------------------------------
Address 37: Navigation Labels: 4E0-910-88x-37.lbl
Part No SW: 4E0 910 888 F HW: 4E0 919 887 M
Component: MNS US H51 0990
Revision: 00000000 Serial number: 395D$087512878
Shop #: WSC 02335 785 00200
VCID: 313479684D20DCA2309-8064

No fault code found.

-------------------------------------------------------------------------------
Address 42: Door Elect, Driver Labels: 4F0-910-793-42.lbl
Part No SW: 4F0 910 793 E HW: 4F0 959 793 E
Component: TSG FA H12 0210
Revision: 00000000 Serial number: Ba
Coding: 0051947
Shop #: WSC 02327 785 00200
VCID: 2C0A681C6A02B14A03F-8078

No fault code found.

-------------------------------------------------------------------------------
Address 46: Central Conv. Labels:. 4F0-910-289.lbl
Part No SW: 4F0 910 289 J HW: 4F0 907 289 J
Component: Komfortgeraet H27 0220
Revision: 02200027 Serial number: 01109362430000
Coding: 4618269
Shop #: WSC 02335 785 00200
VCID: 313479684D20DCA2309-8064

Subsystem 1 - Part No: 1K0 951 605 C
Component: LIN BACKUP HORN H03 1301

1 Fault Found:
01134 - Alarm Horn (H12)
012 - Electrical Fault in Circuit
Freeze Frame:
Fault Status: 01101100
Fault Priority: 3
Fault Frequency: 98
Reset counter: 70
Mileage: 69226 km
Time Indication: 0
Date: 2007.06.16
Time: 13:43:02


-------------------------------------------------------------------------------
Address 47: Sound System Labels: 4F0-910-223-BO.lbl
Part No SW: 4F0 910 223 J HW: 4F0 035 223 G
Component: DSP-High C6 H10 0240
Revision: PROD_01 Serial number: 00000000082262
Coding: 0000026
Shop #: WSC 02324 785 00200
VCID: 251C9D3809E88002DC1-8070

No fault code found.

-------------------------------------------------------------------------------
Address 4F: Centr. Electr. II Labels: 4F0-910-280.lbl
Part No SW: 4F0 910 280 HW: 4F0 907 280 C
Component: ILM Beifahrer H12 0100
Revision: Serial number: 00000000175505
Coding: 0012014
Shop #: WSC 02323 785 00200
VCID: 5EEEF2D46C3E13DADDB-800A

No fault code found.

-------------------------------------------------------------------------------
Address 52: Door Elect, Pass. Labels: 4F0-910-793-52.lbl
Part No SW: 4F0 910 793 E HW: 4F0 959 792 E
Component: TSG BF H12 0210
Revision: 00000000 Serial number: a `
Coding: 0051947
Shop #: WSC 02327 785 00200
VCID: 2C0A681C6A02B14A03F-8078

No fault code found.

-------------------------------------------------------------------------------
Address 53: Parking Brake Labels: 4F0-910-801.clb
Part No SW: 4F0 910 801 C HW: 4F0 907 801 A
Component: EPB CDEC0080 H04 0080
Revision: --H04---
Coding: 0007022
Shop #: WSC 02145 785 00200
VCID: 20128C2C16CA652AAF7-8074

2 Faults Found:
02442 - Function Lamp in Control Head
009 - Open or Short to Ground
Freeze Frame:
Fault Status: 01101001
Fault Priority: 6
Fault Frequency: 44
Reset counter: 69
Mileage: 69224 km
Time Indication: 0
Date: 2007.05.17
Time: 02:41:40

Freeze Frame:
Voltage: 13.46 V
Count: 65

02443 - Control Head
012 - Electrical Fault in Circuit - MIL ON
Freeze Frame:
Fault Status: 11101100
Fault Priority: 2
Fault Frequency: 87
Reset counter: 63
Mileage: 69224 km
Time Indication: 0

Freeze Frame:
Voltage: 12.32 V
Count: 44


-------------------------------------------------------------------------------
Address 55: Headlight Range Labels: 4F0-910-357.lbl
Part No SW: 4L0 910 357 HW: 4L0 907 357
Component: AFS 1 H01 0040
Revision: 00000001 Serial number:
Coding: 0000016
Shop #: WSC 02325 785 00200
VCID: 6984D108A5706462389-803C

Subsystem 1 - Part No: 4F0 941 329 D
Component: AFS-Modul links H01 0010

Subsystem 2 - Part No: 4F0 941 329 D
Component: AFS-Modul rechtsH01 0010

1 Fault Found:
02628 - Sensor for Swivel Module Position; Right
008 - Implausible Signal - MIL ON
Freeze Frame:
Fault Status: 11101000
Fault Priority: 2
Fault Frequency: 1
Reset counter: 69
Mileage: 69323 km
Time Indication: 0
Date: 2025.03.28
Time: 19:58:45


-------------------------------------------------------------------------------
Address 56: Radio Labels: 4E0-910-541.lbl
Part No SW: 4E0 910 541 Q HW: 4F0 035 541 L
Component: TUNER EU/US/RDW H42 0620
Revision: 00000000 Serial number: 394D0087887364
Coding: 0000002
Shop #: WSC 02324 785 00200
VCID: 2E0E62145C1EC35A2DB-807A

No fault code found.

-------------------------------------------------------------------------------
Address 61: Battery Regul. Labels: 4F0-910-181.clb
Part No SW: 4F0 910 181 F HW: 4F0 915 181 B
Component: J0644 BEM H12 0760
Revision: 00000000 Serial number: 00000000066007
Shop #: WSC 03325 444 58713
VCID: 241A803C02D2790ACBF-8070

Subsystem 1 - Part No: 4F0 915 105 D
Component: von VA0 1234567890
Coding: 344630393135313035442056413031323334353637383930
Shop #: WSC 11377 004 1048576

No fault code found.

-------------------------------------------------------------------------------
Address 62: Door, Rear Left Labels: 4F0-910-795.lbl
Part No SW: 4F0 910 795 E HW: 4F0 959 795 E
Component: TSG HL H21 0210
Coding: 0051754
Shop #: WSC 02327 785 00200
VCID: 2E0E62145C1EC35A2DB-807A

No fault code found.

-------------------------------------------------------------------------------
Address 65: Tire Pressure Labels: 4F0-910-273-BA.clb
Part No SW: 4F0 910 273 B HW: 4F0 907 273 A
Component: Reifendruck 3 H05 0100
Revision: 00050100 Serial number: 00000700070492
Coding: 0062422
Shop #: WSC 02145 785 00200
VCID: 2216862418C6773AB93-8076

No fault code found.

-------------------------------------------------------------------------------
Address 67: Voice Control Labels: 4E0-910-75x-67.lbl
Part No SW: 4E0 910 754 Q HW: 4E0 035 753 A
Component: SDS 3501 US H46 0630
Revision: 00000000 Serial number: 00000804020186
Shop #: WSC 12336 024 394758
VCID: 343A707CB232E98A5BF-8060

No fault code found.

-------------------------------------------------------------------------------
Address 6C: Back-up Cam. Labels: 4L0-910-441.clb
Part No SW: 4F0 910 441 HW: 4L0 907 441 A
Component: J772__Rearview 0050
Revision: --H12--- Serial number: 525PA8-J842053
Coding: 1000304
Shop #: WSC 02145 785 00200
VCID: 5DECF5D8613808C2C41-8008

No fault code found.

-------------------------------------------------------------------------------
Address 72: Door, Rear Right Labels: 4F0-910-795.lbl
Part No SW: 4F0 910 795 E HW: 4F0 959 794 E
Component: TSG HR H21 0210
Coding: 0051754
Shop #: WSC 02327 785 00200
VCID: 2E0E62145C1EC35A2DB-807A

No fault code found.

-------------------------------------------------------------------------------
Address 76: Park Assist Labels: 4Fx-910-283.lbl
Part No SW: 4F0 910 283 F HW: 4F0 919 283 F
Component: Parkhilfe 4-Kan H09 0060
Revision: 00H09000 Serial number: 06240809300998
Coding: 0021206
Shop #: WSC 131071 1023 2097151
VCID: 2700973073E49212EED-8072

No fault code found.

-------------------------------------------------------------------------------
Address 77: Telephone Labels: 4E0-910-336.lbl
Part No SW: 4F0 910 336 E HW: 4E0 862 335
Component: Handyvorb2 H18 0950
Revision: 00000000 Serial number: 00000005029592
Coding: 0010900
Shop #: WSC 02335 785 00200
VCID: 251C9D3809E88002DC1-8070

No fault code found.

End----------(Elapsed Time: 02:06, VBatt start/end: 14.2V/14.4V)-----------
------------------------------10 Faults Found------------------------------

[Avantly]

Have you checked the wiring between the EPB module and the parking brake switch, and the switch itself? That code seems to indicate that the module considers the input from the switch to be implausible, i.e. stuck switch or switch wiring problem. Or maybe some cola in the switch lol.

[c6enthusiast]

first, i highly appreciate your activity in this forum and thank you for being the one to constantly respond, your knowledge is appreciated. Not sure how i would check the wiring between the two, as the module is in the trunk and the switch is in the center console. I was going to take apart the center console and grab the switch from the donor car and see if this works, but i find it really hard to believe that the switch would just malfunction from a mistake like that, as the parking brake previously worked. Also, it seems as if you did not read the entire post, for if you did you would know the switch is not stuck, nor did i spill cola on it i’m going to attempt to replace the switch on sunday perhaps if nothing else is suggested/ if i can’t find any other info.


Sent from my iPhone using Audizine Forum

[Avantly]

I know you didn't spill anything on it, but have you seen how people treat their cars? I have bought some clean looking cars and then taken apart the (very clean looking) center console and I am not kidding when I tell you that it looked like there was upwards of a gallon of juice/coffee/cola spilled underneath some time before I bought it. I've found the same thing inside window and door lock switches, and one time inside the entire HVAC system (a large quantity of something sticky had been dumped down the defrost vents at some time in the past and it was covered in years of dust, dirt and everything else lol). Car detailers can work wonders but they rarely disassemble the car while cleaning it xD

In regards to the switch, sure it's not stuck, but I suspect this is not just a normal switch - I'd have to yank the one out of my parts car and test, but for a safety critical switch like this they are likely using some sort of passive diagnostic circuitry - Maybe a resistor/resistors in the switch, something which allows the EPB module to be certain that when it sees a request to disengage the parking brake, it is definitely the user(switch) requesting it, and not some loose/damaged wire, etc. I.e. the switch is probably not just a normal on/off toggle type switch contact, but instead has some specific resistance which must be present in each position for the EPB module to consider the input valid. I could be wrong but I see this technique used in a lot of safety related switches in EU cars. The reason I am so keen on the switch is because from what I can tell, this code seems to strongly indicate implausible switch input. To further solidify this theory, I believe that the 024442 code is referencing the LED which is in the parking brake switch itself. Low current LED's in Audis generally do not burn out, so this is very interesting!
The other possibility could be that the contacts in the switch have just failed... Again, maybe from some cola long ago in its past (lol), or maybe just due to age. Or something was dropped on it. Etc.

To test the wiring, if you have access to both ends, you can do something simple like disconnecting it at both ends, then carefully shorting each pin together, one at a time, and checking resistance with a multimeter on the other end. The resistance you see for a good wire would be very low - Just the resistance of your multimeter test leads + resistance of the contacts and wiring harness which wouldn't be more than a couple ohms.

If it wasn't raining cats and dogs outside I'd go check my parts car right now, I might be able to take a look at it in the morning. I have two C6 parts cars and the console is off one of them so the switch is already accessible.

[c6enthusiast]

right, but to test the wiring the center console gotta come apart anyway. not sure if i’ll be able to get to it this upcoming week, and honestly having a functioning parking brake is not very important to me this car has been a great project and i’m honestly just excited to have it on the road and running and driving as a 40k mile car (quite a nice experience). When the center console is out, i will check the wiring and resistance, or since im there ill just swap the switch and hope it works


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[c6enthusiast]

i also believe that because the voltage could have been too low (from the battery being disconnected) and therefore more current had to be pushed through to the LED, and therefore it likely burnt out. Not sure if that correlates to anything else related to the switch though, and it is indeed a very interesting case but a very stupid combination of mistakes.


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[Avantly]

It shouldn't be possible to burn the LED out due to low voltage. It certainly would for high voltage, however the voltage would have to be quite high for quite a while, and that's assuming they are driving it through a resistor. If they are driving it with a constant current circuit then even with high voltage you wouldn't burn it out.

I'll take a look at mine ASAP