help wanted with power drain

[ChiefUno]

Hi guys

A while back when I got my S8 I took it to be washed. After this I saw that I had water in the trunk, where the radio, nav and soundsystem is located.
I had a new(used) radio installed as this failed.
Ever since this I´ve had power drain.
I´ve had a new battery fitted both by audi and again 6 months later, by another shop as I didnt know why the power got drained.
I found out its because the car never goes to sleep, when I lock the car.
The only way to make it sleep, is if I pull one of the fuses for either the Nav unit, the radio or the soundsystem.
I had the local Audi dealer do a test and they suspect the control head ( Interface box) to be faulty. However they wouldnt guarantee it. If they were to fix this it would set me back around £1300. I´d rather not do this as they wouldnt guarantee anything.
What I find odd, is that they started fault finding behind the glove compartment where the interface box is located, and not where my issue started.
I´ve tried to disconnect the Nav unit and put in a loop on the MOST and when this is in place, the car goes to sleep.
That made me think that maybe it was the nav unit, that was the culprit, however, after replacing this unit, the car still wont go to sleep.
I have bought a second hand interface box, but havent gotten around to installing it yet.

What would you guys suggest that I do, to get rid of this error?

[neeldub]

Have you had a full VCDS scan performed and do you have the KESSY keyless system?

[ChiefUno]

Yes I have and I also have keyless system.
There is no error on my interface box however I do have an error on my can gateway and on one of my doorhandles.

I just can't seem to understand why if I put the most loop in place, that it then shuts down as it should

[Mechcanico Lee]

What have we got on the m.o.s.t

Nav
Amplifier?
Telephone ?
Dab ?
Radio ?
Television ?

What’s the fault code for the gateway ?

If you put a meter inline with the battery how many amps is it pulling out when locked up after say 25mins

[ChiefUno]

Nav
Radio
Amp
Phone

00470 - Company Comfort Databus in Single Wire
011 - Open Circuit
Freeze Frame:
Fault Status: 01101011
Fault Priority: 3
Fault Frequency: 95
Reset counter: 71
Mileage: 200805 km
Time Indication: 0
Date: 2017.11.22
Time: 12:12:16

I havent tested with meter in line

[neeldub]

What's the error code from your door handle.. I have a strong hunch that it could be the culprit as i was experiencing power drain everyday as the locking button on the driver door handle was faulty. Once i replaced that, then the power drain vanished.

I had the following code on my car:

=============================================
Address 42: Door Elect, Driver Labels: 4E1-910-802-42.lbl
Control Module Part Number: 4E1 910 802 B HW: 4E2 959 802 F
Component and/or Version: Türsteuer.FS BRM005 0180
Software Coding: 0028462
Work Shop Code: WSC 02313 785 00200
VCID: 20486A13F3B91346AA-8074

1 Fault Found:

02124 - Exterior Door Handle Switch
008 - Implausible Signal
Freeze Frame:
Fault Status: 01101000
Fault Priority: 3
Fault Frequency: 0
Reset counter: 101
Mileage: 148464 km
Time Indication: 0
Date: 2017.10.16
Time: 19:55:36
=============================================

[neeldub]

Originally Posted by ChiefUno

Nav
Radio
Amp
Phone

00470 - Company Comfort Databus in Single Wire
011 - Open Circuit
Freeze Frame:
Fault Status: 01101011
Fault Priority: 3
Fault Frequency: 95
Reset counter: 71
Mileage: 200805 km
Time Indication: 0
Date: 2017.11.22
Time: 12:12:16

I havent tested with meter in line

I wouldn't worry about this error code as I have the same from time to time and it doesn't seem to do anything to the operation of any of the systems.