Battery drain problem

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den310

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I recently saved a 2004 A3 2.0TDi sport from being scrapped by my non mechanically minded brother to hopefully fix up and the first problem I want to address is a constant battery drain of around 1.7 amps when everything is off. My meter covers DC amps.

I took out each fuse one at a time to try and narrow it down but no significant drop noticed so wondered if anyone else had similar and what was it?

A scan showed an issue with the steering and convenience unit, I don't have the exact log at the moment, will have it scanned again soon to see what it showed exactly.

It did have the usual problem with the micro switch in the boot catch but that has been resolved for a while.

Can anyone suggest what to take out of circuit to help find the battery drain or any other suggestions?

Thanks.
 
Does it have factory bluetooth or nav?

Check fuses on right side of dash & under the bonnet.
 
NHN said:
Does it have factory bluetooth or nav?

Check fuses on right side of dash & under the bonnet.
Click to expand...
No to both and I did those fuses one by one and the ones in the engine bay and no real drop from anything, only a couple of hundred milliamps.
 
It has to drop as everything is fused, bizarre.
 
My thoughts entirely, that's why I am here. I am wondering if the diode in the alternator may have gone or something like that so when I can get to the alternator will disconnect that entirely and see what occurs. I may have missed a fuse, will try again and write a list of them and tick them off when done to avoid missing any.
 
You said you took out fuses, but again there are some bigger ones which are bolted :) Definitely have to check those!!
 
Keram said:
You said you took out fuses, but again there are some bigger ones which are bolted :) Definitely have to check those!!
Click to expand...
Ahh.. Yes OK that's true, I only unplugged fuses. Will take a look at those also. Thank you. :yes:
 
Does it have a factory headunit?

If you have errors with the convenience unit then this could well be the cause of the problem as I think this may stay alive when you lock the car (99% of ccts turn off after around 5 mins after locking).
 
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nluk100 said:
Does it have a factory headunit?

If you have errors with the convenience unit then this could well be the cause of the problem as I think this may stay alive when you lock the car (99% of ccts turn off after around 5 mins after locking).
Click to expand...

Yes it has the symphony 2 unit. A friend who is a mechanic said to test the battery drain after locking the car giving it some minutes to see that the drain on the battery should drop if all is well so similar to what you are saying. The first fuses I took out were to do with the convenience unit hoping that would prove it was that but no, not conclusive yet. When the battery went flat I left the car for about 3 days with the battery was connected but I did not lock the car since it was in the garage.
Thank you.
 
My mechanic friend was right. I had the clamp meter on the battery and it showed a drain of a good 1.7 amps. I locked the car and waited and in less than a minute the drain dropped to 500mA and was still dropping until I unlocked the car again when it went back up so me not locking the car and leaving it for a few days caused the battery to drain. On to the next few issues now. :thumbs up:
 
den310 said:
I recently saved a 2004 A3 2.0TDi sport from being scrapped by my non mechanically minded brother to hopefully fix up and the first problem I want to address is a constant battery drain of around 1.7 amps when everything is off. My meter covers DC amps.

I took out each fuse one at a time to try and narrow it down but no significant drop noticed so wondered if anyone else had similar and what was it?

A scan showed an issue with the steering and convenience unit, I don't have the exact log at the moment, will have it scanned again soon to see what it showed exactly.

It did have the usual problem with the micro switch in the boot catch but that has been resolved for a while.

Can anyone suggest what to take out of circuit to help find the battery drain or any other suggestions?

Thanks.
Click to expand...

My first Audi had a similar issue to this, couldn't for the life of me work out why it was draining. I did notice that the red triangle on the dash (emergency indicator lamp) stayed on all the time. I eventually had someone come out and after some digging found that there was an issue with the alarm sensor in the front passenger door, it needed replacing.
 
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