Battery Drain - don't want to hijack any other thread!
 

As described elsewhere by Mechanico Lee, I think I have a battery drain problem caused by the external buttons on the door handles. Ive just started spotting errors with VCDS as below and I've [by chance] seen my Gateway and MMI panel come on briefly in the dark long after I've locked the car.

Lee, if you're reading this I'd be grateful for how you found the 'button drain problem' and more imporrtantly, what you did to fix it. But any other help would be greatly appreciated. I'm going mad with my car battery being flattened after only one day without use. [And I've CTEK charged it overnight beforehand only to see the voltage drop to 11.88V 36 hours later if the car's not used.] :mad:

VCDS scan looks like this for Right Rear Door:
================================================
Address 72: Door, Rear Right Labels: 4E0-910-802.lbl
Part No SW: 4E0 910 802 A HW: 4E0 959 802 C
Component: Türsteuer.HR BRM002 0060
Coding: 0026914
Shop #: WSC 02311 785 00200
VCID: 1E33B919C96614B1DD-804A

1 Fault Found:
02126 - Central Locking Button; Exterior Door Handle
008 - Implausible Signal
Freeze Frame:
Fault Status: 01101000
Fault Priority: 3
Fault Frequency: 0
Reset counter: 206
Mileage: 363584 km
Time Indication: 0
Date: 2017.01.05
Time: 14:07:20
=================================================
And reading the ECU measurement blocks I get:

Address 72: Door, Rear Right (4E0 910 802 A)

14:34:12 Group 001: General
00000000 Door Status
10 Button Status <--- This is the crucial flag as the 1 is the external button and it's on all the time!
1110 Voltages and Databus Status
12.72 V Voltage Supply

14:34:12 Group 002: Window Regulator Buttons (Local)
Not Oper. WR-Button (Local)

14:34:12 Group 003: Window Regulator
0.0 % Window Regulator Position
21.0 Window Regulator Motor Temperature
0011010 Window Regulator Status
Still Window Regulator Movement

Regards - Julian

I've got the same issue.
Had it since I've owned the car, 've put it down to the kessy system as most of my handles don't work, one way or the other.

I've got four new handles sat in my kitchen (don't tell the wife) waiting to be fitted but I got to buy new soft close latches before I fit these.

be interested if it just kessy that's doing it or not.

I should explain that until recently, two of my buttons haven't worked for years but they didn't show up in VCDS scans. The one causing me problems is the third one that's just started to cause VCDS errors and battery problems.

All the car's buttons were tested with the measurement block function and the good one and the two bad ones don't register that they're being 'pushed' all the time like the third one does!

Julian

I have two buttons down, no VCDS errors about them though.
It would be great if someone with an old handle can cut the grey soft rectangle out of the button and see what the hell is underneath.

Hello all , what I found when the car is locked up and 'asleep' if you press the outer handle button it brings the body module awake this pulls out around 9 amps for around a 90 seconds .
What I noticed especially when it had been raining if I walked near the car you would hear it re lock ....this is without touching the handles or pressing the fob .

It's not such that the handles constantly draw from the battery it's that when its asleep it constantly going awake , asleep , awake , asleep through the night and it's this that drags it down , i proved it by taking the fuse out that does the keyless entry system .

But with my car it's not just that ...again when it's been raining and I lock the car sometimes it would un lock itself ....if i put the keys away from the car it would stay locked but if I walked near it with the keys it would un lock itself so something in the passive sensing side of the handle on seeing the keys close by would allow it to un lock ..... in fact it has just started doing this again but I know it's the drivers rear handle .

Under the little grey button in the handle is just a simple micro switch , I took the little pad out months ago messing with it because water was getting in ....I re sealed it with silicone sealer and it had behaved it's self till recently ...I will have to get a new handle ....work in progress !!

What I would say with any parasitic battery drains is to find out the drain amperage first this gives you a clue as to what it is , some drains have like a cycling effect some are just a constant draw , a cycling effect is normally a module of some sort .

My car goes to sleep like this ....after locking it after about 5 mins it's down to 1.5 amp draw then after around 10 mins its fully asleep which is a 40 milli amps from a car with as many electrical systems as the a8 I see that as acceptable .
Range Rover sports and Discoverys take around 20 mins to go sleep normally between 40 and 70 milli amp on them ive found .

I use a pico scope for a lot of my work but I have just bought this of eBay ......it's a superb little tool for quick hook up and general testing purposes ....think it was £28 delivered and it's pretty accurate against the pico scope

http://i618.photobucket.com/albums/t...psbfq3bd0s.jpg







http://i618.photobucket.com/albums/t...psts7fkm4b.jpg

If you get one make sure it has the Ncv setting as the part number on it does not always come up with the 2 amp current setting on the tool

My battery problem came back today having had a night of rain - she's been good since its been dry or frosty, so I have her going in for a new handle on Thursday (part has to come from Germany then be sprayed up) as the O/S rear handle has been playing up.

Its costing £174 fitted (includes part and paint)

Will keep you posted

I have a similar problem and I also suspect the door locks. Mine are being changed in a couple of weeks, so I'll post back with my findings.

Bloody stupid design!

Thanks for all your responses and comments guys. +++

Lee:

1. "... I took the little pad out months ago messing with it because water was getting in ...".

How did you do this?

2. "I proved it by taking the fuse out that does the keyless entry system ..."

Which fuse is that? Can't find reference to it anywhere I've looked ...

3. "I use a pico scope for a lot of my work ..."

Could you explain what this does?

4. the Uni_T UT210E device

How do you use that usefully on the A8? Can I check my current draw overnight?

1781C:

"Its costing £174 fitted (includes part and paint)"

Is that including labour as well? And who's doing it for you?

[I was led to believe it was nearer £350 per door in the past, which I why I've left mine].:(

Julian