2nd Gen R56 Cooper S 2008 R56 something is drawing down my battery!

Discussion in '2nd Generation: 2007+ R55 through R61' started by kentuckynet, Feb 23, 2013.

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  1. kentuckynet

    kentuckynet New Member

    May 18, 2010
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    #1 kentuckynet, Feb 23, 2013
    Car goes to sleep in about 15 seconds(as it should), all interior lights go out etc.

    but

    If you pull the neg side of the battery something is using 10 volts of draw.
    also
    When you put the neg side back onto the battery it is a big spark!
    (lot of draw)
    We removed the power supply to the fueses under the hood and there is no spark there so whatever it is appears to being drawn from the fuses at the passenger footwell.

    I assume all the computers to the car plug in at this footwell fuse box, i was not able to unplug the 5 or so of those.

    I removed each fuse one at a time and watched the draw and nothing changed. All fuses are good.

    We also removed the power supply going to the alternator and its not that.

    Only codes are from a tpms issue and i wouldnt think thats it.

    HELP>>>>>>>>>>
     
  2. Jason Montague

    Jason Montague New Member
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    Jan 5, 2010
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    #2 Jason Montague, Feb 23, 2013
    :cornut: 1st post-Welcome to MA. I have an 08 R56 also but i've never had the problem that you describe. Have no fear as we do have more knowledgeble people around here and some of them will come along and help you. Please list the code that was thrown. We have a list of the codes in our library by the way.

    Jason
     
  3. kentuckynet

    kentuckynet New Member

    May 18, 2010
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    #3 kentuckynet, Feb 23, 2013
    only code is the front left RDC control unit, when you try and reset the tpms it shows inactive and will not reset.
    All air pressure in the tires is correct....i assume on of the transmitters is bad.
    I removed the fuse for this tpms and it did not change the current draw from the battery
     
  4. killrickykill

    killrickykill New Member

    Jul 4, 2014
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    #4 killrickykill, Jul 4, 2014
    Good Morning, I didn't actually check for when this thread started so hopefully you've found a fix to your problem, but in case you haven't, I joined up specifically to offer what little advice I could. Now bear in mind that I am an Acura mechanic (at a dealership) and so there will obviously be differences, however electricity is electricity and doesn't discriminate.

    We see draw problems a lot and they are generally always the same culprit on an Acura, the handsfreelink system, but even when it's not it's pretty simple to track down, though we do have the added benefit of wiring and circuit diagrams. So first things first, start at the battery and take a look at how the cables from the positive side and see where they go, there are usually only a couple and will go to the undehood fuse/relay block and the alternator. From there power will go to various places, so, set up your multimeter to test amp current draw, which I assume you know how to do by bridging the negative post and cable. Now I noticed you say your car "sleeps" after only about 15 seconds? While I can't absolutely rule that out since I've never tried this on my own mini, generally just because the lights all go out in the car and everything doesn't mean the car is "asleep", the ecu and other control units will generally stay "awake" for about 10-15 minutes, in my experience, before fully going into sleep mode and your draw will drop to sleep levels, which on an Acura are about 0.02 Amps; so just to be safe I would wait that time to see where the draw levels are. If your car is still drawing which I'm guessing it is, then start at the underhood fuse/relay block and start unplugging fuses and relays one at a time and watching the meter to see if one of them drops the draw by being unplugged. You should be able to isolate power from the ENTIRE car directly from the underhood fuse block. This is where a circuit diagram comes in handy so see if you can find one. These circuits function like a tree kind of so as you isolate and rule out certain branches keep going until you find the branch group that is drawing and go further down the tree until you locate the source of the draw and replace the offending unit. I will go take a look at my mini and then try to go into more specific detail if you still need it later
     

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