Mitsubishi 380. Manual — part 674

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-107

(2) Measure the voltage using special tool MB991219

(Inspection test harness), by inserting probe into the wiring
harness-side connector A-02.
NOTE: The special tool (Inspection test harness)
MB991219 for connector pin contact pressure should be
used. The test probe should never be forcibly inserted, as it
may cause a defective contact.

(3) Turn the ignition switch to the "ON" position.
(4) Measure the voltage between connector A-02 terminal 25

and body ground, using inspection test harness
(MB991219).
NOTE: The special tool (Inspection test harness)
MB991219 for connector pin contact pressure should be
used. The test probe should never be forcibly inserted, as it
may cause a defective contact.

Q: Does the voltage measure 4.0 V or less?

YES : If the voltage measures 4.0 V or less, go to Step 27.

Diagnose CAN bus lines thoroughly by referring to

P.54C-323

.

NO : If the voltage measures more than 4.0 V, replace the

ABS-ECU.

16DB482A

TEST
HARNESS

CONNECTOR: A-02

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-108

STEP 27. Check the CAN_H line (communication line only)

between the ENGINE-ECU connector and A/T-ECU

connector for a short to the power supply. Measure voltage

at ENGINE-ECU connector B-21.
NOTE: When diagnosing CAN BUS on vehicles with
manual transmission (M/T) please disregard A/T ECU and
its circuits.

CAUTION

A digital multimeter should be used. For details refer to

P.54C-4

.

CAUTION

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

P.54C-4

.

(1) Disconnect ENGINE-ECU connector B-21 and A/T-ECU

connector B-19, and measure the voltage at the harness
side of ENGINE-ECU connector B-21.

(2) Turn the ignition switch to the "ON" position.

16DB480A

COVER

ENGINE
CONTROL
UNIT

AIR
CLEANER

A/T
CONTROL
UNIT

16DB400A

COVER

ENGINE
CONTROL
UNIT

AIR
CLEANER

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-109

(3) Measure the voltage between ENGINE-ECU connector

terminal 64 and body ground.

OK: 1.0 V or less

CAUTION

Strictly observe the specified wiring harness repair proce-
dure. For details refer to

P.54C-5

.

Q: Does the voltage measure 1.0 V or less?

YES : If the voltage measures 1.0 V or less, go to Step 28.
NO : If the voltage measures more than 1.0 V, repair the

wiring harness between ENGINE-ECU connector and
A/T-ECU connector.

STEP 28. Check the CAN_H line inside the A/T-ECU for a
short to the power supply. Measure the voltage at A/T-ECU
connector B-19.

CAUTION

A digital multimeter should be used. For details refer to

P.54C-4

.

CAUTION

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

P.54C-4

.

(1) Disconnect A/T-ECU connector B-19.
NOTE: When diagnosing CAN BUS on vehicles with
manual transmission (M/T) please disregard A/T ECU and
its circuits.

16DB483A

HARNESS SIDE: B-21

TEST
HARNESS

16DB480A

COVER

ENGINE
CONTROL
UNIT

AIR
CLEANER

A/T
CONTROL
UNIT

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-110

(2) Connect special tool MB992045 (A/T check harness) to the

A/T-ECU and the wiring harness, and measure the voltage
at special tool MB992045 (A/T check harness) connector
B-19.

(3) Turn the ignition switch to the "ON" position.
(4) Measure the voltage between special tool MB992045 (A/T

check harness) connector B-19 terminal 13 and body
ground.

OK: 4.0 V or less

NOTE: When diagnosing CAN BUS on vehicles with
manual transmission (M/T) please disregard A/T ECU and
its circuits.
Q: Does the voltage measure 4.0 V or less?

YES : If the voltage measures 4.0 V or less, diagnose CAN

bus lines thoroughly by referring to

P.54C-323

.

NO : If the voltage measures more than 4.0 V, replace the

A/T-ECU.

STEP 29. Check intermediate connector C-29 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.

CAUTION

The strand end of the twisted wire should be within 10 cm
(4 inches) from the connector. For details refer to

P.54C-4

.

Q: Is intermediate connector C-29 in good condition?

YES : Go to Step 30.
NO : Repair the damaged parts.

16DB484A

TEST
HARNESS

SPECIAL TOOL
MB992045

A/T-
ECU

MEASURE AT THIS CONNECTOR

SPECIAL TOOL MB992045
CONNECTOR

52DB014A

CONNECTOR: C-29