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      04-17-2017, 03:55 PM   #63
RossBMWZseries
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Drives: '11 E92 328i LCI & '06 Z4MR
Join Date: Jun 2014
Location: San Juan TX

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Quote:
Originally Posted by jdoublehcubed View Post
you've got a bad component or control module somewhere that's draining the power. i haven't had this issue on my z4, but I've seen it on other cars and you've described the issue exactly. no apparent battery/alternator issues but a frequent dead battery. on my audi tt I had a bad chip in the dashboard that was causing the issue, and I had another car where it was the radio head unit. i'm not sure if there are any components on the z4 known to commonly fail in this way, maybe someone will chime in.

one way to diagnose the issue is to start disconnecting individuals modules and see if the issue goes away. since your battery is dying overnight, you've got a pretty large current draw so once you stumble on to the right component there should be no question that you've got it. i would start with the radio and amplifier. you can probably disconnect those by pulling a fuse. you can also go through and pull other fuses one at a time to try to find the right module.

you can try googling "how to find current leakage in a car" for some tips.
Thanks for the response jdoublehcubed. I haven't done anything to my car but TWO things; I had a buddy of mine (that happens to have a Z4MR as well) code several things in my car using his laptop. Also, I swapped the ashtray in the Z4 for the AUX tray. Ever since these 2 updates, my car's been dying. If I pull the fuse, how long do I have to have it pulled out for? Overnight to determine if my car wakes up "dead"?
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2014 BMW X5 Sdrive35i F15
2011 BMW 328i E92 LCI
2006 BMW Z4 M Roadster E85
2013 BMW S1000RR K46 R.I.P.
1998 BMW Z3 Roadster 1.9L E36 SOLD
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