Theory of Operation
WARNING: This page is about a different car, the 2011 RAM Pickup. However, it is still accessible from the selected car via links, so may be relevant.
The vehicle speed sensor signal is a direct input to the Anti-Lock Brake (ABS) module. The ABS module busses the wheel speed signal over the CAN C bus. The Powertrain Control Module (PCM) receives the message from the CAN bus.