Unknow Issue.

[David021]

Hello!

I have a problem with my 2013–2016 Audi A4 B8.5 2.0 TDI 177 hp Quattro 6-speed manual.
I’m getting the "Steering Lock: Contact Workshop" error on the dashboard. In VCDS, the error appears in 05 - Acc/Start Auth. as 03026 - Enabling Terminal 15 with faults 006 and 009 (Short to Ground / Short to Plus).
The ignition turns on, but after pressing the clutch and pushing the key again, the car doesn’t even attempt to crank. Instead, it turns the ignition off.
If I hold the clutch pedal down with the key in the ignition slot, it eventually starts after multiple attempts—sometimes on the second try, sometimes on the 20th. This error and starting issue are intermittent. If I clear the error or disconnect the battery, it works for 1–2 days (or less). The battery is fine; it was replaced last year and coded to the car. The steering lock also functions correctly—the wheel has never locked or failed to unlock.
This issue occurred last year. The mechanic opened the plenum chamber under the windscreen, cleaned the cables in the junction box (center of the plenum) with sandpaper, and sprayed them with contact cleaner. I repeated this process this year, but it didn’t help, and the cables showed no visible oxidation.
Worth noting: I’ve had drainage problems in the plenum chamber. Water pooled there because the drains were blocked. The issue happened last year during heavy rain and has recurred this year under similar conditions.

Here is the VCDS scan for the 05 - Acc/Start Auth. (BCM2) module:
(If needed I can provide a full scan for the car)

 

Address 05: Acc/Start Auth. (J393) Labels:. 8K0-907-064-05.clb
Part No SW: 8K0 907 064 FD HW: 8K0 907 064 FD
Component: BCM2 2.0 H10 0602
Revision: 00002001
Coding: 03A20000000000000000
Shop #: WSC 06335 000 00000
VCID: 77ABEBC16FCEBA623E1-8022

Subsystem 1 - Part No SW: 8T0 959 754 D HW: 8T0 959 754 D
Component: FBSAUDIB8 IDG H60 0072
Serial number: 0812000010933010

Subsystem 2 - Part No SW: 8K0 905 852 E HW: 8K0 905 852 E
Component: J764 ELV MLB H40 0046
Serial number: 2312000005203016

2 Faults Found
03026 - Enabling Terminal 15:
009 - Open or Short to Ground
Freeze Frame:
Fault Status: 00101001
Fault Priority: 2
Fault Frequency: 1
Reset counter: 97
Mileage: 353326 km
Time Indication: 0
Date: 2025.06.11
Time: 16:20:33
03026 - Enabling Terminal 15:
006 - Short to Plus - MIL ON
Freeze Frame:
~ Raw, Index/Key Err.: 229 226 127

(no units): 1.4673
Raw, Index/Key Err.: 187 055 193

 

Edited 7 hours ago by David021