Battery Drain

ChasinD1

New Member
Hello all,
My wifes A2 has recently had flat battery issues, its had a new alternator and battery in the last year. It'll go about 2-3 days without a run before it won't start. The central locking works depending on the cars mood, more often than not it choses not to be operational. I've had the neutral off the battery and tried to measure the current draw on the MA setting on the multimeter with doors closed/lights off etc and dont get a contsant reading, it fluctuates between 200 and 350MA. From what Ive read on here chances are its the CCU (2001 F model). Anyone any suggestions ? I see from previous threads there is a member called Lau in Germany who repairs them.

Thanks in Advance

Neil
 
Welcome Neil.

Young Tom @timmus is our electrical wizard and may be along to offer some counsel in due course. Whilst not local to you, he is in the UK.

Good luck with a resolution.

Darren
 
You can do the same test with fuse box to identify power loses. Remove fuse, connect multimeter in its place. Do this with all the fuses.
 
I had this problem with my 2001 TDI. It turned out to be the CCCU. I sourced a second hand one from an auction site (search Audi A2 Comfort) and it cleared the problem. It was very easy to change. You just peel back the nearside carpet, remove the floor panel and replace it.
 
Thanks everyone. If I replace the CCCU do I need to have the keys recoded ?
Not if the CCCU came with key(s), but you need to to swap the top half of the key(s) with your old key(s) to deal with the immobiliser and keep the physical key blade(s) to match your car's locks.

Yes if no keys with CCCU - you will need VCDS assuming compatibility.

Andy
 
In my case, on my original 2002 AMF it was down to one of the window motor/controllers.
I think the drain was about 170mA and it did cause a small area of the CCU to be warm, so it was easy to assume it was down to the CCU.
I used my other A2's CCU to eliminate it; so it may be worth borrowing one to try?
Good luck
Martin
 
In my case, on my original 2002 AMF it was down to one of the window motor/controllers.
I think the drain was about 170mA and it did cause a small area of the CCU to be warm, so it was easy to assume it was down to the CCU.
I used my other A2's CCU to eliminate it; so it may be worth borrowing one to try?
Good luck
Martin

The link in post 4 covers that very diagnostic procedure and fix for the window motor unit completed by Rob from WOM Automotive on a customers car

Cheers Spike
 
I had this problem with my 2001 TDI. It turned out to be the CCCU. I sourced a second hand one from an auction site (search Audi A2 Comfort) and it cleared the problem. It was very easy to change. You just peel back the nearside carpet, remove the floor panel and replace it.
Hi. Interesting post, thanks. I found one on ebay but with this in the description:

"This unit will require coding to your vehicle.
THIS ITEM IS NOT PLUG AND PLAY. VCDS (or similar) + Knowledge is required."

So I'm a bit cautious. Was this not your experience then? Cheers.
 
Hi. Interesting post, thanks. I found one on ebay but with this in the description:

"This unit will require coding to your vehicle.
THIS ITEM IS NOT PLUG AND PLAY. VCDS (or similar) + Knowledge is required."

So I'm a bit cautious. Was this not your experience then? Cheers.
Morning,

Without seeing pictures of the eBay item I don’t know if it comes with the bottom half (lock/unlock buttons) of the remote fob.

I assume it doesn’t from the description you mention.

If it does indeed come with matched/paired remote fobs, it may still require coding with VCDS as the A2 it came from may not if had the same options as yours own A2.

Access to VCDS and a little bit of reading on this great forum will see you right though, do not go to a local garage for them to do this unless they have good knowledge of what they’re doing. They will also charge for this service which most members on here with VCDS will do FOC.

If you do have access to VCDS I am happy to assist you over a video call to obtain your A2 coding from your failing CCCU so it can be transferred onto the replacement CCCU.

If you want to take me up on my offer then just PM me with your phone number, I will then video call you when you have the replacement CCCU and VCDS fires up in your A2. It’s not a lengthy process.

Kind regards,

Tom
 
Morning,

Without seeing pictures of the eBay item I don’t know if it comes with the bottom half (lock/unlock buttons) of the remote fob.

I assume it doesn’t from the description you mention.

If it does indeed come with matched/paired remote fobs, it may still require coding with VCDS as the A2 it came from may not if had the same options as yours own A2.

Access to VCDS and a little bit of reading on this great forum will see you right though, do not go to a local garage for them to do this unless they have good knowledge of what they’re doing. They will also charge for this service which most members on here with VCDS will do FOC.

If you do have access to VCDS I am happy to assist you over a video call to obtain your A2 coding from your failing CCCU so it can be transferred onto the replacement CCCU.

If you want to take me up on my offer then just PM me with your phone number, I will then video call you when you have the replacement CCCU and VCDS fires up in your A2. It’s not a lengthy process.

Kind regards,

Tom
Many thanks Tom. I'm still isolating the issue to the CCCU at the moment. It's a battery drain issue which seems, from the forum, to commonly originate from the CCCU. But there are quite a few other potential causes too. So I'll do some further investigation first but may well be back with you to take up your kind offer. Cheers, Steve
 
No problems Steve,

I along with everyone will be here to help once you’re ready.

Project OEM had a battery drain (2-3 days and it was dead) issue when I first purchased it. I was trying all sorts of diangnistics with information I was armed with from plenty of reading here on the Forum. I was checking all the wiring harnesses that I could get to to see if someone had created the issue with a bridge repair somewhere.

In the end the boot light not going out when the boot was closed gave the fault away. Our friend Tom @timmus said most likely the CCCU at the centre of this. Quickly fitted an AF CCCU that was fitted in my dead work stead and all sorted.

If after you complete your fault finding and do end up going for a replacement CCCU, but purchase a CCCU without remote fobs then I will also help out where I can, this will involve you sending the CCCU to me along with the fobs and I’ll return it with the fobs matched along with it being correctly coded to the options installed in your A2. Of course if you do have access to VCDS I can take you through it over a FaceTime (or equivalent). What ever option you choose, it will be free of charge as it would only be 20-30 minutes of my time. I just like to help out where I can.

Kind regards,

Tom
 
The CCU remains powered up for a few minutes after the ignition is switched - that's why you can still operate the windows. You should then check the drain current, not immediately after turning the ignition off. It should decline to about 40mA, from memory.

RAB
 
The CCU remains powered up for a few minutes after the ignition is switched - that's why you can still operate the windows. You should then check the drain current, not immediately after turning the ignition off. It should decline to about 40mA, from memory.

RAB
Thanks. Is there as far as you know a switch which should make the CCCU disengage and if so could its failure explain why the source of the battery drain might be the CCCU failing to disengage? Cheers.
 
Thanks. Is there as far as you know a switch which should make the CCCU disengage and if so could its failure explain why the source of the battery drain might be the CCCU failing to disengage? Cheers.
There is no such switch, unfortunately. The CCCU always remains partially active such that it can respond to central locking requests, but it shuts down other functions after a set period of time.

Cheers,

Tom
 
Thanks. Is there as far as you know a switch which should make the CCCU disengage and if so could its failure explain why the source of the battery drain might be the CCCU failing to disengage? Cheers.
Do your electric windows still function 10 minutes after switching off ignition? If yes, it's your CCU that's not switching off. You could, of course, also have an additional battery drain.

RAB
 
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