Mitsubishi 380. Manual - part 726

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-315

STEP 10. 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. 

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, diagnose CAN 

bus lines thoroughly by referring to 

P.54C-323

 

<Vehicles with multi-center display >.

NO :  If the resistance does not measure 120 

± 20 Ω, go to 

Step 11 .

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-316

STEP 11. Check the CAN bus lines (communication line 
only) between A/T-ECU and the ENGINE-ECU. Measure the 
resistance between 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.

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

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.

16DB480A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

A/T

CONTROL

UNIT

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-317

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

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

OK: 2 ohms or less

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

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 12.

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 A/T-ECU 
connector B-19 and the ENGINE-ECU connector 
B-21. 

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-318

STEP 12. 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 connector 

B-21 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 13.

NO :  If the resistance does not measure 120 

± 20 , replace 

the ENGINE-ECU.

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

16DB512A

COMPONENT SIDE: B-21

TEST
HARNESS

TEST
HARNESS