Mitsubishi Colt Ralliart. Manual — part 302

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54D-37

FUNCTION

When diagnosing the CAN bus lines, the M.U.T.-III
measures the voltage of CAN_H and CAN_L line and
detects the short to power supply or earth.

TROUBLE JUDGEMENT CONDITIONS

The M.U.T.-III judges the trouble when it is impossi-
ble to receive the periodically sent data and the volt-
age of CAN_H or CAN_L line is less than 1.0 volt.

POSSIBLE CAUSES

• Malfunction of the wiring harness

• Malfunction of the connector

• Malfunction of each ECU

DIAGNOSIS PROCEDURE

STEP 1.Check the CAN bus lines. Resistance
measurement at B-32 diagnosis 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

.

NOTE: This inspection allows you to check that there
is a short to power supply in either CAN_H line or
CAN_L line. Thus, in the following steps, check the
CAN bus line that is defective.

AC509191

Connector: A-08

Harness side

AD

A-08 (GR)

AC401056

AB

Connectors: B-15, B-32

B-32 (B)

Harness side

B-32

B-15

Harness side

B-15 (B)

(1) Disconnect engine-ECU <M/T> or

engine-CVT-ECU <CVT> connector A-08 and
combination meter connector B-15, and measure
the voltage at the harness side of diagnosis
connector B-32.

Main

Index

Group

TOC

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54D-38

CAUTION

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

P.54D-5

.

(2) Ensure that the negative battery terminal is

disconnected.

AC313908 AD

Harness side: B-32

Test
harness

(3) Resistance between B-32 diagnosis connector

terminal No.14 and body earth (CAN_H)

OK: 1 k

Ω or more

AC313908 AC

Harness side: B-32

Test
harness

(4) Resistance between B-32 diagnosis connector

terminal No.6 and body earth (CAN_L)

OK: 1 k

Ω or more

Q: Is the check result normal?

YES <all of the measurement results show 1 k

Ω or

more> :

Go to Step 10.

NO <Either of CAN_H line or CAN_L line the
measurement results show 1 k

Ω or more> :

Go to

Step 2.

STEP 2. Resistance measurement at 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 intermediate connector (B-40), and

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

CAUTION

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

P.54D-5

.

(2) Ensure that the negative battery terminal is

disconnected.

AC313908 AC

Female side: B-40

Test
harness

(3) Resistance between B-40 intermediate connector

terminal No.3 and body earth (CAN_H)

OK: 1 k

Ω or more

Main

Index

Group

TOC

AC313908 AF

Female side: B-40

Test
harness

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54D-39

(4) Resistance between B-40 intermediate connector

terminal No.4 and body earth (CAN_L)

OK: 1 k

Ω or more

Q: Is the check result normal?

YES :

<1 k

Ω or more> Go to Step 7.

NO :

<less than 1 k

Ω> Go to Step 3.

STEP 3. Voltage measurement at 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 joint connector (CAN1), and measure

at the wiring harness side.

CAUTION

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

P.54D-5

.

(2) Ensure that the negative battery terminal is

disconnected.

(3) Measure the resistance between each of B-03

joint connector (CAN1) terminals and body earth.

<CAN_H>

•

AC313908

AC313908AG

Harness side: B-03

Test
harness

Terminal No.2 and body earth

•

AC204738

AC204738

AC204738NE

Harness side: B-03

Test
harness

Terminal No.6 and body earth <vehicles with

ASC>

•

AC313908AJ

Harness side: B-03

Test
harness

Terminal No.7 and body earth

•

AC313908

AC313908AK

Harness side: B-03

Test
harness

Terminal No.8 and body earth

OK: 1 k

Ω or more

Main

Index

Group

TOC

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54D-40

<CAN_L>

•

AC313908

AC313908AH

Harness side: B-03

Test
harness

Terminal No.3 and body earth

•

AC313908

AC313908AI

Harness side: B-03

Test
harness

Terminal No.4 and body earth

•

AC313908

AC313908AN

Harness side: B-03

Test
harness

Terminal No.11 and body earth

•

AC204738

AC204738

AC204738NF

Harness side: B-03

Test harness

Terminal No.12 and body earth <vehicles with

ASC>

OK: 1 k

Ω or more

Q: Is the check result normal?

YES <all of the measurement results show 1 k

Ω or

more> :

Repair the wiring harness between joint

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

NO <The resistance between terminal No.2 or 4 and
body earth is less than 1 k

Ω> :

Repair the wiring

harness between joint connector (CAN1)
and diagnosis connector.

NO <The resistance between terminal No.3 or 8 and
body earth is less than 1 k

Ω> :

Repair the wiring

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

NO <The resistance between terminal No.6 or 12
and body earth is less than 1 k

Ω> :

Go to Step 5.

NO <The resistance between terminal No.7 or 11
and body earth is less than 1 k

Ω> :

Go to Step 4.

STEP 4. M.U.T.-III CAN bus diagnostics (B-133
ETACS-ECU connector disconnected)

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

.

AC313826 AB

Connector: B-133

Harness side

B-133 (GR)

(1) Disconnect the ETACS-ECU connector, and

diagnose by using the M.U.T.-III.

Main

Index

Group

TOC