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

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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

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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

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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