Principles of Operation: HS-Can

The HS-CAN network 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 network CAN circuits allowing network modules to communicate with each other. The HS-CAN is a high speed communication network used for instrument cluster, powertrain control module (PCM) and anti-lock brake system (ABS) module communication.

The CAN bus (+) and bus (-) circuits must always be terminated. The network termination of the CAN bus takes place inside the 2 termination modules, the PCM and the instrument cluster, by resistors rated at 120 ohms, located across the (+) and (-) circuits. The resistors are wired in parallel to the network bus circuits for a total operating resistance of 60 ohms on a good network.

The HS-CAN network operates at a maximum data transfer speed of 500 Kbps and remains operational at a degraded level when certain circuit faults are present. The HS-CAN bus may remain operational with only one termination resistor present.

The following modules are on the HS-CAN network:

• PCM with integrated 4x4 CM
• ABS module
• Instrument cluster

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