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

Castle Coachworks in Northampton are doing it, this price includes supply of part, spray to match, remove door card, fit, reassemble. They recon it should take 45 minutes to do once the part has been arrived and sprayed.

I highly recommend their work, but I can't guarantee this will solve your problem, I am in the same boat, but odds are on it being the KESSY system based on all other comments

I would like to see some pics of the door handle itself being disassembled too. Can you take out the pad without damaging or cutting permanently plastic welded stuff or so?

Not sure if the photos comment was meant for me, but I'll ask castle to give me back the old one so I can perform some surgery on it, see whats going on under there

Julian
I was trying to remove the grey button with a small pick ...i torn the rubber boot of it and ended up buggering it up somewhat ..... i cannot see how you could take the handle apart without wrecking it .

The Uni t 203 is just a hand held volt meter / inductive amps clamp ....its handy just for doing quick ' asleep testing ' .

On the our pico scope i can set say a 24 hour time base and leave it hooked up to the car in the workshop overnight ...... then where i see a blip on the graph i can expand it out to see whats happening in more detail .




Passenger side end of dash fuse box , 42 vehicle access system





http://i618.photobucket.com/albums/t...pszwkwolp9.jpg



Where i would start is put your amp meter on the battery ..... i would say an inductive one is a better choice here as most multimeters will not carry the load that these a8s have when they wake .....you will end up popping fuses on the meter all the time , or use a meter and use a shunt between battery and heavy lead .
Roll the boot catch over lock the car and just watch the meter in the boot for a time to see what amps its pulling .

Battery shunt



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

More useful comment guys and in particular, Lee, thanks for your input and pictures. +++

So the Pico is, I now assume, an expensive device that can plot voltages and /or currents over time, presumably using an inductive clamp, so you can leave it and look later?

And what do you mean by 'rolling the lock over'? [When I'm charging I just prop my boot open slightly with a polystyrene block and note that the central locking 'locks up' but doesn't light the door LEDs]. :(

Oh, and by the way, my car's outside so with no cover I need to prepare for any bad weather ...

Julian

Yes pico scope is a 4 channel automotive scope i use a bit , but just hand held inductive amps clamp well get you a long way ...aslong as it can go quite low down to 50 milli amps say

Rolling the locks over means with say a screw driver blade click the catch mechanism over so the car sees the doors or boot as shut so you can lock the car up and set the alarm ...its so the car is in the same condition as you leave when you lock it up .

So amps clamp around battery earth lead ,roll boot latch over , lock car and watch amps draw after 10 mins see what sort of amps draw you have

Julian,
Just to clarify.
When Lee says "scope" it is short for "oscilliscope"
It gives a visual view of waveforms in an electric circuit.
Hope that helps.

Lee and Ray; thanks for the latest comments.

Didn't realise I could 'ping' the boot lock so that the car thought it was locked - useful tip.

Just need to get an appropriate 'clamp solution' for reading amp flow and a spell of clear weather ...

Julian

Update: Just ordered clamp meter from ebay [but it's from China, so will take a while :(]

Have you ordered the one like ive got Jullian ? I got mine from an english seller was here in 2 days .

When using it always make sure you go to dc as when you flick through ranges it always defaults to ac , and always zero it when using amps function after changing ranges and when zeroing it dont have clamp around the cable

Its really handy ive been using it on all kinds at work

Have you ordered the one like ive got Jullian ? I got mine from an english seller was here in 2 days .

When using it always make sure you go to dc as when you flick through ranges it always defaults to ac , and always zero it when using amps function after changing ranges and when zeroing it dont have clamp around the cable

Its really handy ive been using it on all kinds at work

It's identical Lee; I used the model number but all of them on Ebay seemed to be from China / Hong Kong.

After I ordered, I thought to look on Amazon and could have got one from the UK :(

Julian

Does it stop the drain if you pull the fuse on 42?

What else does it affect?

I haven't tried Lee's approach of 'proving' it by taking out the KESSY fuse; I'm not sure how he proved it and I don't have the equipment that he has access to. [The superb Pico scope with its logging appears to be upwards of £1000 :(]. But I'm hoping the £30 clamp meter will at least show 'something' when it turns up.

However, while I'm waiting for it, I looked at some wiring diagrams yesterday :Confused:.

I can see from VCDS Measuring Blocks that the right rear door lock button appears to be constantly 'on', so I might try taking out the fuse for the door ECU instead. From what I can work out that is fuse 41 in the right dash panel fuse box. I could live with no access via that door for a week to see if I still get the drain.

Julian

If that works I might do that.
I got be changing my handles for a while yet.
Got to order four latches as well.

Will it stop the start stop button?

The £30 amps clamp wil do the job just fine , have you access to a compressor and air blower , squirt Wd down the handle button and blow it out then see if you can get the button to work in the data blocks .

If he doors have individual fuses for the out station ecm yes pull that to issolate that door then see if the battery is getting dragged down

When you get your amps clamp you can see what it is pulling when asleep and you will be able to pull fuses to issolate electrical circuits and see the difference on the amps draw , rather than guessing if there is a higher amps draw than the norm .

Update - Trying the door fuse
 

I haven't pulled the 'Advanced Entry' fuse that Lee indicated yet as I wasn't sure of the consequence of disabling the whole entry system. [I presume Lee disabled it overnight and used the sophisticated Pico system to watch the current map for the whole night to see there were no regular pulse peaks of drain increase from the now disabled entry system].

But while I await my clamp meter from China, I thought I'd try and test what happens when I take out the right rear door fuse from the right hand end of the dashboard. [This is the 7.5A fuse at location 41]. I did this because I assumed all contact with the door would be lost and the 'always on' button wouldn't be able to wake up the Kessy system.

But it didn't work as I thought it would. :( The door was disabled so that the lock and handles wouldn't work, but VCDS could still 'see' the Rear Right Door ECU and I could still look at the ECU Measuring Blocks. And if VCDS can see the ECU, the ECU would obviously continue to 'wake' the Kessy system while the car was off and locked. So the ECU interface to other ECUs in the car is not routed through the fuse path.

I've tried making sense of the circuit diagrams for the 2005 on Right door ECU [Section 87 of the Current Flow PDF] but can't work out how to isolate the ECU signal to prove or disprove the door ECU as the cause of my drain. I guess I could get the door panel off and cut the wire from the button to the ECU - at least I can work out what colour that is from Section 87. :)

Julian

Perhaps just unplug the handle!?

Or unplug loom connector on from the door at the B post junction ...or don't worry to much about pulling that Kessy fuse ...yes some things will stop working but hey hoe ....if you want to prove a fault .......

I don't know how we managed in days gone by ....my 2L Cortina did not even have keyless entry ....you had to put the key in the door and actually turn it to get in !! Rediculous for sure .....!! come to think about it my Datsun Sunny was the same ....MEH !!! putting keys in the lock .....indeed ....

If only it was that easy :( Getting the door panel off is non-trivial on these cars.

"Or unplug loom connector on from the door at the B post junction" ex Lee: hadn't thought about attacking the loom but I'm not sure what's involved there ...

HOWEVER; following an earlier suggestion by Lee by, I flooded the door button with AF Spray - an aerosol lubricant my Dad left me years ago - and I seemed to have stopped the button being 'live'. VCDS now reports '0' in the measuring block for the button rather than '1' that's been constant for recent weeks.

So I'm keeping my eye on the battery level for the next few days in the hope it's temporarily solved. I can then attack the problem with the knowledge that the button IS the cause.

Julian

Just checked mine and the passenger door is saying the button is pressed.

I'm going to look at spraying the button.

Julian,
Did you just spray it under the rubber or on the rubber?

Scott, I just sprayed large amounts of AF-Spray on and under the button and pushed it a few times. Not sure if it's still off as I've been a bit busy. But the clamp meter has finally arrived. :)

==================================================

Sorry for delay, been:

a) away to see my Mum - her 80th Birthday,
b) decorating
c) sorting out insurance when foreign artic. hit my house [in a residential cul-de-sac] at midnight. [Driver from Moldova who only spoke Russian and Romanian, Cab unit with CZ:Czech Republic plate, Trailer with D:Germany plate, Haulage Company based in Austria] Try sorting that lot out :mad:

Julian

Battery drain - it's not the door button
 

Now that I've got other things out the way, I sadly [for me, anyway] have to report that I still have a battery drain despite the 'Right Rear Door' ECU no longer reporting that the button is being pressed continuously. :Confused:

So now I've got to reinvestigate from scratch :-(

I've got a little bit of help from the new VCDS Battery History tool, which does at least tell me how much went out the battery in the last idle time, but I might have to resort to the 'measure the fuse current' trick and try and detect a small[ish] current flow.

However, one thing puzzles me; since I have to open the driver/passenger door [or boot] to get at the fuses and opening the doors triggers the gateway and entry system, does anyone have any suggestion as to how to overcome this issue please?

Julian

Open all doors and bootlid but then close all the latches so the car thinks its closed leaving drivers door latch till last, press the buttons for interior and tilt monitoring then close the latch on drivers door and lock the car so the alarm arms as normal but without interior monitoring or tilt sensing. Your free then to check the fuses etc once the car goes to sleep

When I was diagnosing battery drain on mine, I used a normal multimeter which I connected in series with the battery on the Amps range. You need a meter that can deal with large current flow, and you must not attempt to start the car with the meter in the circuit.

The wires to the meter were fine enough that I was able to have the wires outside the car with the meter and the car fully locked as usual and could monitor the current draw in realtime from the kitchen window.

But my D3 seemed to go to sleep with all the doors locked, but the boot open. After 15 mins the meter said the below.
http://forum.a8parts.co.uk/attachmen...0&d=1444725462

However my drain problem disappeared all on its own and I've not had it since, I do however have another problem in part brought about because the D3 is hardly used these days.

Useful tips ...
 

Delboy/mannyo; thanks for those replies; some things to think about there +++

I don't have 'under cover' storage though, so I need some good dry [and warmer] weather first.

But, some queries though before I try it!

1) Do I just close the latches by poking a screwdriver into the door / boot locks and pressing the lever?

2) I presume that will that stop the doors closing? That is; don't try it in the rain!

3) How do I unlock the doors afterwards? Just click the remote?

4) How long, in practice, before the car shuts down? Is it always about 15 mins?

Thanks - Julian

Hi Julian,

I think Uwe posted this on the Ross-Tech forums. I found it really useful. It suggests an hour to wait until the car shuts down.

https://youtu.be/lRcj1fQcWwU

Thanks Tony; that was useful.

I think it answers all my questions ...

Julian

Nice video Tony, shows exactly what I was talking about, added it to my bookmarks as its a great one to keep. +++