A marine propulsion system includes a first controller area network (CAN) bus communicatively connecting two or more devices to facilitate communication of CAN messages therebetween. The system further includes a helm controller (HCM) associated with the propulsion device and having an HCM CAN transceiver to facilitate receipt and transmission of CAN messages by the HCM on the first CAN bus. The HCM is configured to receive a silence CAN message via the first CAN bus and then determine whether the silence CAN message is directed to itself. If so, then the HCM will cease transmitting any CAN message on the first CAN bus and/or cease CAN-related diagnostics in response to the silence CAN message so as to reduce traffic on the CAN bus.