SRS codes don't clear with a battery power cycle; you need an SRS reset tool. There are some BMW SRS reset tools on e-bay for about $35 US.
I honestly don't know anything about that test, but the name implies that it is a system start-up test that looks for a stable power supply voltage. It could have been triggered by the system starting with only the battery maintainer and no battery to stabilize the voltage.
Last edited by Blacklane; 01-28-2013 at 06:41 PM.