Mitsubishi Colt Ralliart. Manual - part 305

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54D-49

FUNCTION

The M.U.T.-III judges a short between CAN_H and 
CAN_L line when all data from ECU cannot be 
received while checking periodically sent data from 
each ECU even if the voltage is normal.

TROUBLE JUDGEMENT CONDITIONS

The M.U.T.-III judges the trouble when it is impossi-
ble to send and receive the all ECU periodically sent 
data and the voltage of CAN_H and CAN_L line is 
4.0 volts or less and 1.0 volt or more.

POSSIBLE CAUSES

• Malfunction of the wiring harness

• Malfunction of the connector

• Malfunction of each ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-01 joint connector 
(CAN2), B-03 joint connector (CAN1), B-40 
intermediate connector

AC313820

Connectors: B-01, B-03, B-40

B-40

B-40

AN

B-01

B-03

B-01, B-03

CAUTION

The strand end of the twist wire should be within 
10 cm from the connector. For details refer to 

P.54D-5

.

When checking the joint connector, ensure that its 
wiring harness side and its short pins are not dam-
aged.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the defective connector.

STEP 2. Resistance measurement at the B-40 
intermediate connector.

CAUTION

A digital multimeter should be used. For details 
refer to 

P.54D-5

.

CAUTION

The test wiring harness should be used. For 
details refer to 

P.54D-5

.

AC313820

Connector: B-40

AD

(1) Disconnect the connector, and measure at its 

female-side intermediate connector (at the front 
wiring harness side).

(2) Turn the ignition switch to the OFF (LOCK) 

position.

CAUTION

When measuring the resistance, disconnect the 
negative battery terminal. For details refer to 

P.54D-5

.

(3) Ensure that the negative battery terminal is 

disconnected.

AC313936 AB

Female side: B-40

Test 
harness

Test 
harness

(4) Resistance between B-40 intermediate connector 

terminal Nos.3 and 4

OK: 120 

± 20 Ω

Q: Is the check result normal?

YES : 

<Within 120 

± 20 Ω> Go to Step 3.

NO : 

<Not within 120 

± 20 Ω>Go to Step 7.

Main

Index

Group

TOC

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54D-50

STEP 3. Resistance measurement at the B-03 
joint connector (CAN1).

CAUTION

A digital multimeter should be used. For details 
refer to 

P.54D-5

.

CAUTION

The test wiring harness should be used. For 
details refer to 

P.54D-5

.

AC313820

Connector: B-03

AE

(1) Disconnect the connector, and measure at the 

wiring harness side.

(2) Turn the ignition switch to the OFF (LOCK) 

position.

CAUTION

When measuring the resistance, disconnect the 
negative battery terminal. For details refer to 

P.54D-5

.

(3) Ensure that the negative battery terminal is 

disconnected.

AC313936

AC313936AD

Test 
harness

Test 
harness

Harness side: B-03

(4) Resistance between B-03 joint connector (CAN1) 

terminal Nos.2 and 4

OK: 1 k

Ω or more

AC313936

AC313936AC

Harness side: B-03

Test 
harness

Test 
harness

(5) Resistance between B-03 joint connector (CAN1) 

terminal Nos.3 and 8

OK: 120 

± 20 Ω

AC313936

AC313936AE

Harness side: B-03

Test 
harness

Test 
harness

(6) Resistance between B-03 joint connector (CAN1) 

terminal Nos.7 and 11

OK: 1 k

Ω or more

AC204738

AC204738

AC204738

AC204738

AC204738NI

Harness side: B-03

Test harness

Test 
harness

(7) Resistance between B-03 joint connector (CAN1) 

terminal Nos. 6 and 12 <vehicles with ASC>

OK: 1 k

Ω or more

Main

Index

Group

TOC

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54D-51

Q: Is the check result normal?

YES <all of the measurement results are within the 
normal value> : 

Repair the wiring harness 

between joint connector (CAN1) and 
intermediate connector (B-40).

NO <The resistance between terminal Nos.2 and 4 
is less than 1 k

Ω> : 

Check the diagnosis 

connector, and repair if necessary. If the 
diagnosis connector is in good condition, 
repair the wiring harness between joint 
connector (CAN1) and diagnosis connector.

NO <The resistance between terminal Nos.3 and 8 
is less than 120 

± 20 Ω> : 

Go to Step 4.

NO <The resistance between terminal Nos.6 and 12 
is less than 120 

± 20 Ω> : 

Go to Step 6.

NO <The resistance between terminal Nos.7 and 11 
is less than 120 

± 20 Ω> : 

Go to Step 5.

STEP 4. Resistance measurement at B-15 
combination meter connector.

CAUTION

A digital multimeter should be used. For details 
refer to 

P.54D-5

.

AC401055

AE

Connector: B-15

B-15 (B)

Harness side

(1) Remove the combination meter, and measure at 

the equipment side.

AC204738FM

Equipment side: B-15

Test 
harness

Test 
harness

(2) Resistance between B-15 combination meter 

connector terminal Nos.1 and 2

OK: 120 

± 20 Ω

Q: Is the check result normal?

YES : 

<Within 120 

± 20 Ω> Repair the wiring 

harness between joint connector (CAN1) 
and combination meter connector.

NO : 

<Not within 120 

± 20 Ω> Check the 

combination meter connector, and repair if 
necessary. If the combination meter 
connector is in good condition, replace the 
combination meter.

STEP 5. Resistance measurement at B-133 
ETACS-ECU connector.

CAUTION

A digital multimeter should be used. For details 
refer to 

P.54D-5

.

AC313826 AB

Connector: B-133

Harness side

B-133 (GR)

(1) Remove the ETACS-ECU, and measure at the 

equipment side.

AC204738 FN

68

74

66

65

7273

67

5657

59

58

63

61

70 71

62

53

52

5455

64

69

60

51

Equipment side: B-133

Test 
harness

Test 
harness

(2) Resistance between B-133 ETACS-ECU 

connector terminal Nos.56 and 65

OK: 1 k

Ω or more

Q: Is the check result normal?

YES : 

<1 k

Ω or more> Repair the wiring harness 

between joint connector (CAN1) and 
ETACS-ECU connector.

NO : 

<Less than 1 k

Ω> Check the ETACS-ECU 

connector, and repair if necessary. If the 
ETACS-ECU connector is in good condition, 
replace the ETACS-ECU.

Main

Index

Group

TOC

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54D-52

STEP 6. Resistance measurement at B-142 
steering wheel sensor connector.

CAUTION

A digital multimeter should be used. For details 
refer to 

P.54D-5

.

AC601077AB

Connector: B-142

Harness side

(1) Remove the steering wheel sensor, and measure 

at the equipment side.

AC204738

AC204738

AC204738NJ

Equipment side: B-142

Test 
harness

Test 
harness

(2) Resistance between B-142 steering wheel sensor 

connector terminal Nos.4 and 6

OK: 1 k

Ω or more

Q: Is the check result normal?

YES : 

<1 k

Ω or more> Repair the wiring harness 

between joint connector (CAN1) and 
steering wheel sensor connector.

NO : 

<Less than 1 k

Ω> Check the steering wheel 

sensor connector, and repair if necessary. If 
the steering wheel sensor connector is in 
good condition, replace the steering wheel 
sensor.

STEP 7. Resistance measurement at the B-01 
joint connector (CAN2).

CAUTION

A digital multimeter should be used. For details 
refer to 

P.54D-5

.

CAUTION

The test wiring harness should be used. For 
details refer to 

P.54D-5

.

AC313820AF

Connector: B-01

(1) Disconnect the connector, and measure at the 

wiring harness side.

(2) Turn the ignition switch to the OFF (LOCK) 

position.

CAUTION

When measuring the resistance, disconnect the 
negative battery terminal. For details refer to 

P.54D-5

.

(3) Ensure that the negative battery terminal is 

disconnected.

AC204738

AC204738

AC204738

AC204738

AC204738NK

Harness side: B-01

Test 
harness

Test harness

(4) Resistance between B-01 joint connector (CAN2) 

terminal Nos.1 and 5 <vehicles with ASC>

OK: 1 k

Ω or more

Main

Index

Group

TOC