Circuit/System Description
WARNING: This page is about a different car, the 2013 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.
The Rear Parking Assist Control Module is supplied ignition voltage from the I/P fuse block. When the transmission is in reverse, the system is turned ON, ignition voltage is supplied from the BCM. The Rear Object Sensors are supplied with signal circuits referenced from 8 volts and low reference by the Rear Parking Assist Control Module. The Speaker - Parking Assist is provided with B+ from the Rear Parking Assist Control Module provides a PWM low signal to the speaker to provide an audible alert.