Mitsubishi Colt Ralliart. Manual - part 293

GROUP 54D

CONTROLLER 

AREA NETWORK 

(CAN)

CONTENTS

GENERAL INFORMATION . . . . . . . .

54D-2

SPECIAL TOOL . . . . . . . . . . . . . . . . .

54D-3

TEST EQUIPMENT  . . . . . . . . . . . . . .

54D-4

SERVICE PRECAUTIONS. . . . . . . . .

54D-5

PRECAUTIONS ON HOW TO 

 

REPAIR THE CAN BUS LINES . . . . .

54D-6

EXPLANATION ABOUT THE 

 

M.U.T.-III CAN BUS DIAGNOSTICS  .

54D-7

TROUBLESHOOTING  . . . . . . . . . . . .

54D-13

CAN BUS DIAGNOSTICS TABLE  . . . . . . . 

54D-13

CAN BUS DIAGNOSIS . . . . . . . . . . . . . . . . 

54D-24

CAN COMMUNICATION-RELATED 
DIAGNOSIS CODE (U CODE) 

 

TABLE. . . . . . . . . . . . . . . . . . . . . . . . .

54D-84

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TOC

GENERAL INFORMATION

CONTROLLER AREA NETWORK (CAN)

54D-2

GENERAL INFORMATION

M1548310000267

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 
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 dam-
aged mode, communications can be continued in 
some cases.

STRUCTURE

AC204755

AC204755AF

Engine-ECU
or 
Engine-
CVT-ECU

EPS-ECU

M.U.T.-III

ETACS
-ECU

ABS-ECU
or
ASC-ECU

Steering 
wheel 
sensor

G and 
yaw rate 
sensor

CAN_H

CAN_L

Diagnosis
connector

Combination 
meter
(incorporating 
meter-A/C-ECU)

: Shows sub bus line.

: Shows main bus line.

Terminal resistor

Terminal resistor

Main bus lines

• 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 the two terminal 

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

• The terminal resistors are installed in the 

engine-ECU <M/T> or engine-CVT-ECU <CVT> 
and combination meter (incorporating 
meter-A/C-ECU) to stabilize communication sig-
nals (The terminal resistance is set at approxi-
mately 120 

Ω).

• ECUs are connected in the CAN bus line as fol-

lows.

• Engine-ECU <M/T> or engine-CVT-ECU 

<CVT>

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SPECIAL TOOL

CONTROLLER AREA NETWORK (CAN)

54D-3

• ABS-ECU <vehicles without ASC> or 

ASC-ECU <vehicles with ASC>

• G and yaw rate sensor <vehicles with ASC>

• Steering wheel sensor <vehicles with ASC>

• EPS-ECU

• ETACS-ECU

• Combination meter (incorporating 

meter-A/C-ECU)

SPECIAL TOOL

M1548304200369

Tool

Number

Name

Use

MB991910

MB991826

MB991955

MB991911

MB991824

MB991827

MB991825

a

b

c

d

e

f

DO NOT USE

MB991955

a. MB991824
b. MB991827
c. MB991910
d. MB991911
e. MB991825
f. MB991826

M.U.T.-III 
sub-assembly

a. Vehicle 

Communicati
on Interface 
(V.C.I.)

b. M.U.T.-III 

USB cable

c. M.U.T.-III 

main harness 
A (Vehicles 
with CAN 
communicatio
n system)

d. M.U.T.-III 

main harness 
B (Vehicles 
without CAN 
communicatio
n system)

e. M.U.T.-III 

measure 
adapter

f. M.U.T.-III 

trigger 
harness

CAUTION

For vehicles with CAN 
communication, use M.U.T.-III 
main harness A to send 
simulated vehicle speed. If you 
connect M.U.T.-III main harness B 
instead, the CAN communication 
does not function correctly.
CAN bus diagnostics

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MB991223

a

d

c

b

DO NOT USE

BA

TEST EQUIPMENT

CONTROLLER AREA NETWORK (CAN)

54D-4

TEST EQUIPMENT

M1548304300128

Test equipment

Name

Use

AC000019

Digital multimeter

Checking CAN bus circuit (for resistance and voltage 
measurements)

MB991223

a. MB991219
b. MB991220
c. MB991221
d. MB991222

Harness set

a. Check 

harness

b. LED harness
c. LED harness 

adapter

d. Probe

Continuity check and voltage 
measurement at harness wire or 
connector

a. For checking connector pin 

contact pressure

b. For checking power supply 

circuit

c. For checking power supply 

circuit

d. For connecting a locally sourced 

tester

MB992006

MB992006

Extra fine probe

Continuity check and voltage 
measurement at harness wire or 
connector

MB991970

MB991974

ABS check 
harness

Checking continuity and measuring 
voltage at ABS-ECU <vehicles 
without ASC> or ASC-ECU 
<vehicles with ASC> harness-side 
connector

Tool

Number

Name

Use

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