Principles of Operation: HS-Can

WARNING: This page is about a different car, the 2007 Mercury Mariner and 2007 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

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 multiple modules to communicate with each other. The HS-CAN is a high speed communication network used for the instrument cluster, the powertrain control module (PCM), the anti-lock brake system (ABS) module, and the four wheel drive (4WD) control module communications, and designed for real time information transfer and control. The HS-CAN network 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 following fault chart describes the specific HS-CAN network failures and their resulting symptom:

HS-CAN NETWORK COMMUNICATION FAULT CHART

Failure Description	Symptom
HS-CAN (+) shorted to HS-CAN (-)	No communication
HS-CAN (+) short to voltage	No communication
HS-CAN (-) short to voltage	No communication
HS-CAN (+) short to ground	No communication
HS-CAN (-) short to ground	Unreliable communication
HS-CAN (+) open	Unreliable communication
HS-CAN (-) open	Unreliable communication
Module loss of voltage or ground	No communication
Module internal failure	No communication

The following chart describes the specific CAN network messages broadcast by each module, and the module(s) that receive the message:

CAN NETWORK MODULE COMMUNICATION MESSAGE CHART

Broadcast Message	Originating Module	Network Type	Receiving Module(s)	Sets DTC Type
ABS/trac event in progress	ABS module	HS-CAN	Instrument cluster PCM	Network
ABS/trac indicator on request	ABS module	HS-CAN	Instrument cluster	Network
ABS/trac system configuration	ABS module	HS-CAN	Instrument cluster	Network
ABS/trac system status	ABS module	HS-CAN	Instrument cluster PCM	Network
Actual torque	PCM	HS-CAN	ABS module	Network
Anti-stall active	PCM	HS-CAN	ABS module	Network
Axle ratio	PCM	HS-CAN	ABS module	Network
Barometric pressure	PCM	HS-CAN	ABS module Instrument cluster 4WD control module	Network
Barometric pressure (gateway)	Instrument cluster	MS-CAN	SJB	Network
Brake deactivator switch status	ABS module	HS-CAN	Instrument cluster PCM	Network
Brake fluid level status	ABS module	HS-CAN	Instrument cluster	Network
Brake indicator on request	ABS module	HS-CAN	Instrument cluster	Network
Brake switch status	ABS module	HS-CAN	Instrument cluster PCM 4WD control module	Network
Brake thermal intervention active y/n	ABS module	HS-CAN	Instrument cluster PCM	Network
Catalyst protection active y/n	PCM	HS-CAN	ABS module	Network
Charging system status	PCM	HS-CAN	ABS module Instrument cluster 4WD control module	Network
Clutch pedal position	PCM	HS-CAN	ABS module Instrument cluster 4WD control module	Network
Door ajar status	SJB	MS-CAN	Instrument cluster	Network
Drivetrain type	PCM	HS-CAN	ABS module	Network
Electronic brake distribution status	ABS module	HS-CAN	Instrument cluster PCM	Network
Engine coolant temp	PCM	HS-CAN	ABS module Instrument cluster 4WD control module	Network
Engine off timer	PCM	HS-CAN	ABS module Instrument cluster 4WD control module	Network
Engine RPM	PCM	HS-CAN	ABS module Instrument cluster 4WD control module	Network
Failsafe cooling mode	PCM	HS-CAN	ABS module Instrument cluster 4WD control module	Network
Fuel cap off indicator request	PCM	HS-CAN	ABS module Instrument cluster 4WD control module	Network
Fuel flow data	PCM	HS-CAN	ABS module Instrument cluster 4WD control module	Network
Fuel level input status (filtered)	Instrument cluster	HS-CAN	PCM	Powertrain
Fuel level input status (instant)	Instrument cluster	HS-CAN	PCM	Powertrain
Headlamp status	SJB	MS-CAN	Instrument cluster	Network
Key-in-ignition status	SJB	MS-CAN	Instrument cluster	Network
Maximum available torque	PCM	HS-CAN	ABS module	Network
Minimum available torque	PCM	HS-CAN	ABS module	Network
MIL warning indicator on request	PCM	HS-CAN	ABS module Instrument cluster 4WD control module	Network
Odometer count	ABS module	HS-CAN	Instrument cluster 4WD control module	Network
Overdrive indicator status	PCM	HS-CAN	ABS module Instrument cluster 4WD control module	Network
Park lamp status	SJB	MS-CAN	Instrument cluster	Network
PATS indicator status	PCM	HS-CAN	ABS module Instrument cluster 4WD control module	Network
PATS key status	PCM	HS-CAN	ABS module Instrument cluster 4WD control module	Network
PATS key status (gateway)	Instrument cluster	MS-CAN	SJB	Network
Perimeter alarm status	SJB	MS-CAN	Instrument cluster	Network
Shift and converter status	PCM	HS-CAN	ABS module	Network
Throttle position	PCM	HS-CAN	ABS module Instrument cluster 4WD control module	Network
Torque reduction request	ABS module	HS-CAN	Instrument cluster PCM 4WD control module	Network
Torque transfer actual	4WD control module	HS-CAN	ABS module Instrument cluster	Network
TPMS sensor status (LF, RF, RR, LR)	SJB	MS-CAN	Instrument cluster	Network
TPMS system status	SJB	MS-CAN	Instrument cluster	Network
Transmission gear ratio	PCM	HS-CAN	ABS module	Network
Transmission selector range	PCM	HS-CAN	ABS module	Network
Transmission selector range (gateway)	Instrument cluster	MS-CAN	SJB	Network
Turn signal indicator request	SJB	MS-CAN	Instrument cluster	Network
Vehicle speed	ABS module	HS-CAN	Instrument cluster 4WD control module	Network
Vehicle speed (gateway)	Instrument cluster	MS-CAN	SJB	Network
VIN information	PCM	HS-CAN	ABS module 4WD control module	Network
Wheel speed output (RF, LF, RR, LR)	ABS module	HS-CAN	4WD control module	Network
4WD indicator request	4WD control module	HS-CAN	ABS module Instrument cluster	Network