Parasitic current draw. How to identify the issue?

**sapstar** · 19-07-2021,12:20 PM

I did a current draw test on my Audi A6 C6 today as my battery keeps draining. I get a reading of 5.76Amp with nothing running.

How do I go about identifying the root cause? I have a brand new battery now, but don't want to install it until this is resolved. Can someone please help?

**Crasher** · 19-07-2021,01:02 PM

Pull the fuses one by one and see when the drain goes, remember to fool the inconvenience system by flipping the door and bonnet latches to closed position and have the key out so the CAN BUS shuts down; 5.76 amp is huge so I recon you haven't let the BUS shut down.

**sapstar** · 19-07-2021,01:58 PM

Thanks @Crasher. I can see there are fuses on either sides of the dashboard and on the right side of the trunk. Are there any other fuses?
If I understand correctly, you are suggesting I open the doors to have access to the fuses, but keep the door latches compressed to fool the system (I can do this by just pressing lock on my remote right?). I can just keep the bonnet closed right? I will be connecting the multi meter to the battery in the trunk.

**Crasher** · 19-07-2021,02:45 PM

Trunk? There are four fuse boxes plus other fuses in certain areas such as on the battery but the main ones are SA in the plenum chamber electronics box, SB in the right side of the dash, SC in the left side of the dash and SF is in the left of the BOOT. You need the front door, boot and bonnet open so you have to trip the latches manually otherwise the car will not shut down and don't use the remote, the doors need to remain unlocked and the alarm off.

**sapstar** · 19-07-2021,02:54 PM

Thanks very much @Crasher. I lived for 6 years in US and bought my first car there... So used to calling the boot, a trunk

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**Crasher** · 19-07-2021,03:08 PM

You don't say things like "swap out" or "change out" do you? That would be really awful...

**sapstar** · 19-07-2021,06:45 PM

I do use "swap out" some time unfortunately

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I followed this The BEST Way TO Perform a Parasitic Draw Test - YouTube video to check the fuses which are accessible (both sides of the dash and in the "boot"). I didn't quite know how to reach the fuses in the bonnet.
I measured the voltage and derived the mA values from fuse-charts.pdf (powerprobetek.com). I didn't get any high readings except for a 10a mini fuse on the driver side (Number 19 which was supposed to be blank). It actually looked burnt when I took it out and I replaced it.

I did get a 0.1mV reading of a few of them. Is this normal? It converts to around 50mA each and probably adding up to 0.5 - 0.7A total. I tried "swapping out" a couple of these, but the new ones also were showing 0.1mV so I put the original ones back.

I haven't done a draw test yet, but I don't think the issue will be resolved. The only fuse I replaced was contributing 108mA.

**Crasher** · 19-07-2021,07:25 PM

Private message me your REG and I will check the fuse diagram

**sapstar** · 15-08-2021,05:08 PM

@Crasher I got my car checked by a local mechanic and he did a battery test and told me to first replace the battery and then try the drain test. I replaced with a new battery and did a drain test. I still got over 5Amp. I was unlocking the car, waiting for about 10 mins for everything to go to sleep and then did the test.
I left the mult imeter connected for a few more mins and magically the drain dropped to 0.15 Amp. I think probably the bus didn't completely shutdown when I was testing before. Can you confirm? Do you know how long it takes for everything to shutdown on the car once you unlock?