Section 924 (Electronic Control Modules (Service Information)): Communication: Operation

WARNING: This page is about a different car, the 2018 Fiat 500L. However, it is still accessible from the selected car via links, so may be relevant.

The Controller Area Network (CAN) data bus allows all electronic modules or nodes connected to the bus to share information with each other. Regardless of whether a message originates from a module on the lower speed CAN-B bus or on the higher speed CAN-C bus, the message structure and layout is similar, which allows the Body Control Module (BCM) to process and transfer messages between the CAN buses. The BCM also stores a Diagnostic Trouble Code (DTC) for certain bus network faults.

All modules (also referred to as nodes) transmit and receive messages over one of these buses. Data exchange between nodes is achieved by serial transmission of encoded data messages. Each node can both send and receive serial data simultaneously. Each digital bit of a CAN bus message is carried over the bus as a voltage differential between the two bus circuits which, when strung together, form a message. Each node uses arbitration to sort the message priority if two competing messages are attempting to be broadcast at the same time.

Components The components connected to the CAN-C network are:

BCM (Body Computer Module)
BSM (braking System Module)
MTA (Manual Transmission Automated), if equipped.
EPS (Electric Power Steering), if equipped.
ECM (Engine Control Module)
YRS (Yaw Rate Sensor), if equipped.

Components The components connected to the CAN-B network are:

BCM (Body Computer Module)
IPC (Instrument Panel Cluster)
ECC (Electronic Climate Control), if equipped.
CTM (Convergence Telematic Module), if equipped.
SDM (Sensing and Diagnostic Module)
PAM (Parking Aid Module), if equipped.
RRM (Radio Receiver Module), if equipped.