Modes of Operation

The 14V power module maintains the 12V battery while the vehicle is in propulsion mode but may also support the 12V battery during vehicle charging and vehicle OFF modes.

Pre-Sleep 

Every time the vehicle is turned off the 14V power module will operate for 10 additional minutes to ensure the 12V battery is sufficiently charged. The high voltage contactors remain closed during pre-sleep.

Battery Maintenance Mode 

With the vehicle OFF, the body control module will monitor the 12V battery state of charge (SOC) whenever it wakes up (door unlock, etc.) or 11 hours whichever comes first. If the 12V battery SOC is below about 85% the high voltage contactors are requested closed and the 14V power module will charge the 12V battery until one of the following conditions is met:

• 12V battery SOC reaches 96%
• 2 hour time limit has been reached
• Hybrid/electric vehicle battery SOC drops to 13%

For more information on the 12 V Battery Charging System, refer to Charging System Description and Operation .