Theory Of Operation

WARNING: This page is about a different car, the 2024 RAM ProMaster EV. However, it is still accessible from the selected car via links, so may be relevant.

The VPA system consists of the BCM, the VPAM and two VPA speakers. The BCM receives ignition status, vehicle speed, transmission gear position and engine status over the Controller Area Network (CAN) bus. The BCM sends Local Interface Network (LIN) signals to the VPAM for vehicle speed and sound control. The VPAM includes the front speaker and is hardwired to the rear VPA speaker.

The VPA outputs sound according to vehicle speeds greater than 0 mph/kph, gear position and OFF state of the engine. VPA speaker volume and tone monotonically increases or decreases in frequency proportional to vehicle speed in forward and reverse direction.

The VPA system is active when:

the ignition switch is in the START or ON positions.
the engine is OFF.
the vehicle speed is between 0 and 35 km/h (0 and 22 mph) in forward and reverse.

The VPA system is not active when:

the vehicle is in park.
the engine is running.

The VPAM receives 12 volt battery current on a fused ignition switch output (RUN-START) circuit through a fuse in the Power Distribution Center (PDC). The VPAM receives ground through the body wire harness connected to the body sheet metal. These connections allow the module to be operational whenever the ignition switch is in the START or ON positions.