Circuit/System Description
WARNING: This page is about a different car, the 2011 Chevrolet Volt. However, it is still accessible from the selected car via links, so may be relevant.
The hybrid powertrain control module 2 monitors the voltage values of the charge port wake-up signal circuit and the charge port request signal circuit. When the charge port door release switch is pressed, the switch contact closes and provides B+ voltage to the two signal circuits. The hybrid powertrain control module 2 detects the voltage on the signal circuits and provides a 12 V pulse to the charge port relay, the relay briefly becomes energized which then allows B+ voltage to the charge port door latch which activates and releases the charge port door.