Mitsubishi Outlander XL. Manual — part 1339

GROUP 54D

CONTROLLER AREA NETWORK

(CAN)

CONTENTS

GENERAL INFORMATION. . .

54D-2

STRUCTURE. . . . . ..

54D-3

SYSTEM OPERATION. . . ...

54D-4

SELF-DIAGNOSIS. . . . .

54D-6

CAN BUS DIAGNOSTICS. . .

54D-7

54D-1

GENERAL INFORMATION

M25402000001USA0000010000

CAN, an abbreviation for Controller Area Network, is
an ISO-certified international standard for a serial
multiplex communication protocol*. A communication
circuit employing the CAN protocol connects each
electric control module (ECU), and sensor data can
be shared among, which enables more reduction in
wiring.

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.
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
damaged mode, communications can be continued
in some cases.

54D-2

CONTROLLER AREA NETWORK (CAN)

GENERAL INFORMATION

STRUCTURE

M25402000002USA0000010000

ZC5017670000

Engine control
module

4WD-ECU

SRS-ECU

A/C-ECU

Hands free
module

Satellite
radio tuner

Combination
meter

Wireless control module or
KOS-ECU

Scan tool

Data link
connector

ETACS-ECU

Steering
wheel
sensor

ABS-ECU or
ASC-ECU

Transmissio n
control
module

CAN_H

CAN_L

Main bus line

CAN_H

CAN_L

CAN_H

CAN_L

CAN-C

CAN-B

Diagnosis CAN-C

Terminal resistor

Terminal
resistor

: indicates main bus line

: indicates sub bus line

Occupant
classification-
ECU

Main bus line

｠

OUTLANDER is the first Mitsubishi vehicle with a
gateway function integrated to ETACS-ECU as the
network central ECU. (Refer to GROUP 54A,
ETACS-ECU P.54A-28.)

｠

The CAN system consists of the following three
networks: CAN-B (middle-speed body network),
CAN-C (high-speed power train network), and the
diagnosis CAN-C (diagnosis exclusive network).
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, respectively), 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.

CONTROLLER AREA NETWORK (CAN)

54D-3

STRUCTURE

｠

With CAN-C, the terminal resistors are incorporated
in ECU. Resistors with approximately 120 ohms is
used for the dominant ECU, and that with 4.7
kiloohms is used for the non-dominant ECU.

NOTE:

｠

Dominant ECU: ETACS-ECU and engine ECU

｠

Non-dominant ECU: ECU and sensor on CAN-C
network, excluding ETACS-ECU and engine
ECU

｠

To the CAN bus line, ECU, sensor, and data link
connector are connected as follows for each
network.

CAN-B

｠

A/C-ECU

｠

SRS-ECU

｠

Occupant classification-ECU

｠

Hands free module

｠

Radio and CD player or CD changer <vehicles
without

Mitsubishi

Multi-Communication

System (MMCS)> or CAN box unit <vehicles
with Mitsubishi Multi-Communication System
(MMCS)>

｠

Satellite radio tuner <vehicles satellite radio>

｠

Wireless control module <vehicles without
KOS> or KOS-ECU <vehicles with KOS>

｠

Combination meter

CAN-C

｠

AWD-ECU

｠

Steering wheel sensor <vehicles with ASC>

｠

ABS-ECU <vehicles without ASC> or ASC-
ECU <vehicles with ASC>

｠

Transaxle control module (TCM)

｠

Engine control module (ECM)

DIAGNOSIS CAN-C

｠

Data link connector

SYSTEM OPERATION

M25402000003USA0000010000

ZC5017680000

ECU-1

A

A

A

A

B

B

B

C

C

A

B

Interval "a"

Interval "b"

Interval "c"

C

C

C

B

B

A

A

A

ECU-1

ECU-2

CAN bus

Data frames

Transmission
suspended by
mediation

Re-
transmission

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 10-1000 msec
interval depending on necessity of data.

NOTE:

In the figure above, the data frame A is

transmitted 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.

54D-4

CONTROLLER AREA NETWORK (CAN)

SYSTEM OPERATION