Canbus

CAN is a serial bus system with Multimaster capabilities. This means that many nodes can transmit and receive data at the same time. When a node is transmitting it sends a message, it is put on the BUS. All the nodes then receive the message. Depending on the receiving nodes address, the message is either discarded because it is not meant for that node, or it is accepted and processed. A message can also be given a priority. A message of high priority will obviously take precedence of using the canbus over a lower priority.

One of the outstanding features of Can is the reliability and error detection. The Can controller will register a nodes error and evaluates it to provide necessary errors. One problem with this however is that if one node fails, the whole network can fail. This is another reason for putting Power System and Body Control Modules on a separate network. If your electric window control module fails you still want your car to start!