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      01-26-2012, 02:34 PM   #2
ajsalida
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Drives: 95 M3, 02 R1150GSA, 09 335xi
Join Date: Aug 2010
Location: SW USA

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Same problem here, took it to the dealer and they said battery was good still just needed a charge + "software update". Fine for 6-8 months. Then started doing it again this winter. Always seems to happen when it gets cold. Anyway I charged the battery on 2 amp trickle for 2 days (until light went green on the charger), appears to be fine now.

I think the whole charging system/software is far too complicated for its own good on these cars. There is an internal software model of the battery charge state and alternator output etc., if anything gets skewed it reads "battery discharge while not running" and zeros out the trip odo and other settings. Like when it gets cold.

Really stupid IMHO.