Mitsubishi 380. Manual — part 720

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-291

STEP 13. Check the CAN bus lines between the A/T-ECU
and the ENGINE-ECU (communication line including the
ENGINE-ECU). Measure the resistance at A/T-ECU
connector B-19.

NOTE: when diagnosing CAN-BUS on vehicles with
manual transmission (M/T), disregard A/T-ECU and it’s wir-
ing circuits and check between ABS-ECU and
ENGINE-ECU only.

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, and measure the

resistance at the wiring harness side of A/T-ECU connector
B-19.

(2) Turn the ignition switch to the "LOCK" (OFF) position.

CAUTION

Disconnect the negative battery terminal. For details refer
to

P.54C-4

.

(3) Disconnect the negative battery terminal.

(4) Measure the resistance between A/T-ECU connector

terminals 4 and 5.

OK: 120

± 20 Ω

Q: Does the resistance measure 120

± 20 Ω?

YES : If the resistance measures 120

± 20 Ω, go to Step 16.

NO : If the resistance does not measure 120

± 20 Ω, go to

Step 14 .

16DB480A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

A/T

CONTROL

UNIT

16DB509A

HARNESS SIDE: B-19

TEST
HARNESS

TEST
HARNESS

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-292

STEP 14. Check the CAN bus lines (communication line
only) between A/T-ECU and the ENGINE-ECU. Measure the
resistance at A/T-ECU connector B-19 and ENGINE-ECU
connector B-21.

NOTE: when diagnosing CAN-BUS on vehicles with
manual transmission (M/T), disregard A/T-ECU and it’s wir-
ing circuits and check between ABS-ECU and
ENGINE-ECU only.

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 and ENGINE-ECU

connector B-21, and measure the resistance between each
wiring harness side connector.

(2) Turn the ignition switch to the "LOCK" (OFF) position.

CAUTION

Disconnect the negative battery terminal. For details refer
to

P.54C-4

.

(3) Disconnect the negative battery terminal.

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

16DB480A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

A/T

CONTROL

UNIT

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-293

(4) Measure the resistance between A/T-ECU B-19 connector

terminal 5 and ENGINE-ECU B-21 connector terminal 86.

OK: 2 ohms or less

(5) Measure the resistance between A/T-ECU B-19 connector

terminal 4 and ENGINE-ECU B-21 connector terminal 64.

OK: 2 ohms or less

NOTE: when diagnosing CAN-BUS on vehicles with
manual transmission (M/T), disregard A/T-ECU and it’s wir-
ing circuits and check between ABS-ECU and
ENGINE-ECU only.

CAUTION

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

P.54C-5

.

Q: Do all the resistances measure 2 ohms or less?

YES : If all the resistances measure 2 ohms or less, go to

Step 15.

NO : If either of the resistances measures more than 2

ohms or all the resistances measure more than 2
ohms, repair the wiring harness between the A/T-ECU
B-19 connector and the ENGINE-ECU connector
B-21, and then go to Step 8.

16DB510A

HARNESS SIDE: B-19

TEST
HARNESS

TEST
HARNESS

HARNESS SIDE: B-21

16DB511A

HARNESS SIDE: B-19

TEST
HARNESS

TEST
HARNESS

HARNESS SIDE: B-21

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-294

STEP 15. Check the terminator resistor inside the
ENGINE-ECU. Measure the resistance at ENGINE-ECU
connector B-21.

CAUTION

A digital multimeter should be used. For details refer to

P.54C-4

.

(1) Disconnect ENGINE-ECU connector B-21, and measure

the resistance at the component side of ENGINE-ECU
connector B-21.

(2) Measure the resistance between ENGINE-ECU B-21

connector terminals 64 and 86.

OK: 120

± 20 Ω

Q: Does the resistance measure 120

± 20 Ω?

YES : If the resistance measures 120

± 20 Ω, go to Step 8.

NO : If the resistance does not measure 120

± 20 Ω,

replace the ENGINE-ECU, and then go to Step 8.

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

16DB512A

COMPONENT SIDE: B-21

TEST
HARNESS

TEST
HARNESS