Communications Network - Troubleshooting

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COMMUNICATIONS NETWORK TROUBLESHOOTING - HYBRID

See the Tribute Wiring Diagram for schematic information.

Principles of Operation

Vehicle communication utilizes the controller area network (CAN) communications. The CAN is a method for transferring data among distributed electronic modules via a serial data bus.The vehicle is equipped with 2 module communication networks:

- Medium speed (MS) CAN
- High speed (HS) CAN

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, the front controls interface module (FCIM), the front display interface module (FDIM), the electronic automatic temperature control (EATC) 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:MS-CAN Communication Fault Chart





HS-CAN

The HS-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 HS-CAN is a high speed communication network used for the instrument cluster, the PCM, the ABS module, the occupant classification sensor (OCS), restraints control module (RCM), the battery control module (BCM), the transmission control module (TCM), the power steering control module and the 4X4 control module communications, and designed for real time information transfer and control. The HS-CAN will not communicate while certain faults are present, but will operate with diminished performance with other faults present. The HS-CAN bus may remain operational when 1 of the 2 termination resistors are not present.
The HS-CAN operates at a maximum data transfer speed of 500 Kbps and is designed for real time information transfer and control. The network will remain operational, but at a degraded level when certain circuit faults are present.The following fault chart describes the specific HS-CAN failures and their resulting symptom:HS-CAN Communication Fault Chart





Module Communication Message Charts

The following charts describes the specific CAN network messages broadcast by each module, and the module(s) that receive the message:CAN Module Communication Message Chart