Theory Of Operation
WARNING: This page is about a different car, the 2017 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
The Powertrain Control Module (PCM) receives wheel speed and wheel distance CAN C bus messages from the Anti-lock Brake (ABS) module.
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The ABS Module sends vehicle speed information over the CAN C Bus circuit to the Powertrain Control Module (PCM).