Our 2013 Auris  Hybrid sounds like it is straining when the door is unlocked and opened, and the (brake booster?) motor automatically starts up. The pitch of that motor moves down as it runs. There is no problem with the car in other respects though. It has been like this for months and is getting worse.  Today I checked the 12v battery; with the ignition on it reads 14.4 volts. With the ignition off,  it falls to 12.0 volts after a few minutes; so surprisingly low. Anyone like to