Audi RS4 B7 Parasitic Drain

   #1  

Dino20vt

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I’m getting 60-90 milliamps (fluctuates a lot) with car locked and left for an hour to fully shut down. Pulling fuses in the end panel made little difference.
Is there any other fuses situated elsewhere I could try?
Is this a normal reading?
If not, any usual suspects?
Thanks
 
   #3  

dieseldub

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I second Uwe's suggestion. Measuring mV drop across fuses is a far better method than pulling fuses, especially on modern cars that take quite awhile to go to sleep and can "wake up" again when some fuses are pulled.

Doing an autoscan of every module is also never a bad idea, you may find that some draws are caused by data bus errors, either from a module sending junk info on the bus and keeping other modules awake or a short in a data bus wire somewhere. Sometimes the alternator itself causes a draw.

There are likely some fuses you haven't found yet either, but without knowing exactly which ones you've checked thus far, I've got no suggestions to give. But for sure give the autoscan a try, post results here, and try checking draws via mV drop test... just make sure you close the door and hood latch so those can be left open with the system thinking they're closed. Having either one recognized as being open will also result in a parasitic draw.

Speaking of, on some cars the hood switch also has the radio wired to the same thing. Sometimes radios ground out that circuit and make the system recognize the hood as being open, even though the radio is the cause. Measuring values in the convenience module will easily reveal this if the car doesn't have an indicator to tell you the hood is open.

I've had a couple cars with about a 90 mA draw before because it thought the hood was open, then once I tricked it into recognizing the hood as being closed, the draw went below 30 mA like it should....
 
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Dino20vt

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Thanks both for taking the time to reply.
I’ll give mV drop test a try over the weekend and report back.
The only fuses I pulled where in the right hand side end panel on a RHD car, do you happen to know where there are any more fuses located?
I’m a novice when it comes to VCDS but I have completed an Auto Scan and no faults were present, I'm assuming that scans all modules?
Thanks
 
   #5  

Uwe

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I’m a novice when it comes to VCDS but I have completed an Auto Scan and no faults were present, I'm assuming that scans all modules?
Yes.

-Uwe-
 
   #6  

Dino20vt

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Did the drop test on the main fuses on the end of the dash and also under the scuttle with all the relays, all behaved as they should.
Any other fuses elsewhere I can try?
Thanks
 
   #7  

Jack@European_Parts

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Isn't this most likely a zone open on a central lock mechanism keeping car awake?

Isolate each and observe function of zones or switch condition in VCDS blocks several times or with meter and load light the to qualify and be advised did you know some zones are open when active?
 
   #8  

PetrolDave

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Any faults show in a VCDS Auto-Scan? Posting one here might give some clues...
 
   #10  

PetrolDave

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No faults shown Dave
Still worth posting, as it shows hardware & firmware version numbers which may prompt someone to say there is a known issue which needs a firmware update to solve.

One possible one I know of is the 77 Phone module - one version has been subject to a recall as it could stay turned on and drain the battery (my B7 RS4 - sold a couple of years ago - had a later version as I fitted it myself).
 
   #11  

Dino20vt

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Ok will do tomorrow, thanks for the info.
Re 77 phone module, if that’s the Bluetooth module under the right hand seat in RHD car, I’ve already removed that, unfortunately made no difference.
 
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