If the brakes are squealing, there's a good chance it is the brake pad wear sensor. A new design was implemented in January 2006 and can be identified by its green color.
Resources for the Repair and Maintenance of your 2009 BMW 650i
2009 BMW 650i
2009 BMW 650i Problems
2009 BMW 650i Recalls (Recent)
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The insulated connector for the positive battery cable may have been incorrectly attached to the trunk floor panel, which can lead to a loosening of the bolt connection. Loosening of the connection can cause an increase in electrical resistance and overheating of the cable connection, which could lead to a fire, even when the vehicle is not in use. As a precaution, owners are advised to park outside until the remedy has been completed. Dealers will secure the battery bolt cable connection as necessary to correct this concern.