tion circuit employing the CAN protocol connects
each ECU, and sensor data can be shared among,
which enables more reduction in wiring.
CAN offers the following advantages.

• Transmission rates are much faster than those in

conventional communication (up to 1 Mbps

allowing much more data to be sent.

• It is exceptionally immune to noise, and the data

obtained from each error detection device is more
reliable.

• Each ECU connected via the CAN communicates

independently, therefore if the ECU enters dam-
aged mode, communications can be continued in
some cases.

NOTE:

•

: The regulations have been decided in detail,

from software matters such as the necessary
transmission rate for communication, the system,
data format, and communication timing control
method to hardware matters such as the harness
type and length and the resistance values.

•

: bps=bit per second

STRUCTURE

CONTROLLER AREA NETWORK (CAN)

54C-3

STRUCTURE

M2542000201405

• A gateway function has been integrated to

ETACS-ECU as the network central ECU (Refer
to GROUP 54A

− ETACS-ECU ).

• The CAN system consists of the following two

networks: CAN-C (high-speed power train net-
work) and CAN-C-Mid (middle-speed body net-
work). Each ECU is connected to one of the
networks depending on its functions.

• The CAN bus line consists of two lines, CAN_L

and CAN_H (CAN Low and CAN High, respec-
tively), as well as two terminal resistors (A
twisted-pair cable, highly resistant to noise, is
used for the communications line).

• The CAN bus line connecting two dominant

ECUs is the main bus line, and the CAN bus line
connecting each ECU is the sub-bus line.

ACB05902

M.U.T.-III

Diagnosis
connector

CAN_H

CAN_L

Engine-ECU

Combination meter

ETACS-ECU

CAN-C-Mid

Terminal resistor

CAN_H

CAN_L

CAN-C

: Indicates main bus line

: Indicates sub bus line

OSS-ECU

SRS-ECU

A/C-ECU

Radio and
CD player
or CAN box
unit

KOS-ECU

Steering
wheel
sensor

ABS-ECU
or
ASC-ECU

CVT-ECU

EPS-ECU

4WD-ECU

Electric
tailgate
control unit

Main
bus line

Terminal resistor

Corner sensor/
back sensor
-ECU

SYSTEM OPERATION

CONTROLLER AREA NETWORK (CAN)

54C-4

• With CAN bus, the terminal resistors are incorpo-

rated in ECU. Resistors with approximately 120
Ω is used for the dominant ECU.

NOTE:

•

Dominant ECU: ETACS-ECU, engine ECU
and Combination meter.

•

Non-dominant ECU: ECU and sensor on CAN
network, excluding ETACS-ECU, engine ECU
and Combination meter.

• To the CAN bus line, ECU, sensor, and diagnosis

connector are connected as follows for each net-
work.

CAN-C

• ETACS-ECU

• Steering wheel sensor

• 4WD-ECU <4WD>

• SRS-ECU

• ABS-ECU <vehicles without ASC> or

ASC-ECU <vehicles with ASC>

• CVT-ECU

• EPS-ECU

• Diagnosis connector

• Engine-ECU

CAN-C-Mid

• ETACS-ECU

• OSS-ECU <vehicles with OSS>

• A/C-ECU

• KOS-ECU <vehicles with KOS>

• Radio and CD player <vehicles with radio and

CD player>

• Electric tailgate control unit <vehicles with

electric tailgate>

• CAN box unit <vehicles with MMCS>

• Corner sensor/back sensor-ECU <vehicles

with reversing sensor system>

• Combination meter

SYSTEM OPERATION

M2542000300506

The CAN communication system is described below.

• Each ECU communicating with CAN periodically

sends several sensors’ information on CAN bus
as data frame (called periodical sending data).
For further details, consult the data frame section.

• ECUs requiring data on CAN bus can receive

data frames sent from each ECU simultaneously.

• The data sent from each ECU conducting CAN

communication is transmitted at 0.01

− 1 sec

interval depending on necessity of data.

NOTE: In the figure above, the data frame A is trans-

mitted in "a" intervals, while the data frames B
and C are transmitted at intervals "b" and "c,"
respectively.

• A single ECU transmits multiple data frames.

AC206267

ECU-1

Interval "a"

Interval "b"

Interval "c"

ECU-2

ECU-3

CAN bus

Data frames

AC206267AB

Transmission
suspended by
mediation

Re-
transmission

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