Principles of Operation: Ms-Can

The MS-CAN uses an unshielded twisted pair cable of data (+) and data (-) circuits. The data (+) and the data (-) circuits are each regulated to approximately 2.5 volts during neutral or rested network traffic. As bus messages are sent on the data (+) circuit, voltage is increased by approximately 1.0 volt. Inversely, the data (-) circuit is reduced by approximately 1.0 volt when a bus message is sent. Multiple bus messages can be sent over the CAN circuits allowing multiple modules to communicate with each other. The MS-CAN is used for the instrument cluster (IC), the front controls interface module (FCIM), the front display interface module (FDIM), heating ventilation air conditioning (HVAC) module, the audio control module (ACM), the satellite digital audio receiver system (SDARS) module and the smart junction box (SJB) communications, and is designed for general information transfer. The MS-CAN will not communicate while certain faults are present, but will operate with diminished performance with other faults present. The MS-CAN bus may remain operational when 1 of the 2 termination resistors are not present.

The MS-CAN operates at a maximum data transfer speed of 125 Kbps for bus messages and is designed for general information transfer. The network will remain operational, but at a degraded level when certain circuit faults are present.

The following fault chart describes the specific MS-CAN failures and their resulting symptom: