CAN Bus Messages

The CAN bus is a high speed broadcast network connected between various vehicle control modules. The CAN network carries an extensive list of messages between the different control modules enabling more sophisticated control with reduced complexity. Data on the network is packaged for efficient communication and prioritised according the urgency and importance of the Messages. The bus comprises two wires, which are twisted together to minimise electromagnetic interference (noise) produced by the CAN messages. Refer to Communications Network article.

The transfer box control module is connected on the CAN bus and controls transfer box operation using CAN messages from other control units on the network. Wheel speed, vehicle acceleration, engine torque and speed, gear information, from the automatic transmission, temperature information, car configuration, axle ratios and Terrain Response™ mode inputs, are some of the main signals received by the control module.

In the event of a CAN bus failure the following symptoms may be observed:

• Shift from high to low or low to high inoperative
• Instrument cluster low range warning lamp inoperative
• Warning messages or lamps displayed in instrument cluster.