Brake assist pressure seems to be maintained as needed even when the car is turned 'off'. If there was an internal leak and the pump came on much more often to bring pressure up while the car was parked for an extended period of time would this be a source of traction battery drain or 12 volt battery drain or both and be a possible reason for a 12 volt battery to be dead after two weeks of sitting? Thanks.
Is the traction battery limited only to running the drive train motor? Or does it also maintain the ECM and other drive train systems such as brake assist, a/c, steering assist, etc? What system is the 12 V battery limited to maintaining?
The traction battery is completely disconnected when the Prius is powered down, so no drain will occur for any reason. As for the 12V battery and electric brake accumulator pump, the Prius does not maintain pressure when the car is not in use. You will notice that the Prius pumps up the pressure when you open the drivers door. Tom
Once the Prius is in Ready, the high voltage system, including the traction battery, powers all of the electrical devices. Some are directly powered, such as the A/C compressor, others are powered by the 12V bus through a DC to DC converter. The 12V battery is limited to booting the computers and HV system, and supplying power for the lights, radio, and other 12V items when the Prius is not Ready. Tom
