Mitsubishi 380. Manual - part 409

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-176

STEP 2. Using diagnostic tool MB991958, read the A/T 
diagnostic trouble code.
(1) Connect diagnostic tool MB991958 to the data link 

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Check for A/T diagnostic trouble code.
(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is (P1751) set? (P1751 may be set along with multiple 

DTCs).
YES : Refer to 

P.23A-207

 (P1751): A/T Control Relay 

System.

NO :  Go to Step 3.

STEP 3. Using diagnostic tool MB991958, read the A/T 
diagnostic trouble code.
(1) Connect diagnostic tool MB991958 to the data link 

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Check for A/T diagnostic trouble code.
(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Are (P0753) and (P0743) set? (Multiple DTCs may be 

set).
YES : Go to Step 8.
NO :  Go to Step 4.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-177

STEP 4. Measure the reduction solenoid valve resistance 
at A/T control solenoid valve assembly connector B-108.
(1) Disconnect connector B-108 and measure at the solenoid 

valve side.

(2) Measure the resistance between solenoid valve assembly 

connector B-108 terminals 8 and 10.

Resistance value: 2.7

−3.4 Ω [at 20°C (68°F)]

Q: Is the measured resistance 2.7

−3.4 Ω [at 20°C (68°F)]?

YES : Go to Step 6.
NO :  Go to Step 5.

STEP 5. Measure the solenoid valve resistance at the 
reduction solenoid valve assembly inside the 
transmission.
(1) Disconnect connector B-108-6 and measure at the solenoid 

valve side.

(2) Measure the resistance between reduction solenoid valve 

terminals 1 and 2.

Resistance value: 2.7

−3.4 Ω [at 20°C (68°F)]

Q: Is the measured resistance 2.7

−3.4 Ω [at 20°C (68°F)?

YES : Replace the harness wire between A/T control 

solenoid valve assembly connector B-108 and the 
solenoid valves.

NO :  Replace the reduction solenoid valve. Refer to 

GROUP 23B, Valve Body 

23B-62

.

AC306322

CONNECTOR: B-108

B-108 (GR)

AC

TRANSMISSION
RANGE SWITCH

2

7

1

8

3

9

4

6

10

5

10DB100A

2

7

1

8

3

9

4

6

10

5

B-108 HARNESS CONNECTOR: 
A/T CONTROL SOLENOID 
VALVE ASSEMBLY SIDE

CONNECTOR: B-108-6

VALVE BODY
ASSEMBLY

B-108-6

10DB105A

2

1

10DB101A

B-108-6 HARNESS CONNECTOR: 

REDUCTION SOLENOID 

VALVE SIDE

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-178

STEP 6. Check A/T-ECU connector B-22 and A/T control 
solenoid valve assembly connector B-108 for loose, 
corroded or damaged terminals, or terminals pushed back 
in the connector.
Q: Are the connectors and terminals in good condition?

YES : Go to Step 7.
NO :  Repair or replace the damaged components. Refer to 

GROUP 00E, Harness Connector Inspection 

P.00E-2

.

16DB564A

COVER

AIR

CLEANER

A/T

CONTROL

UNIT

CONNECTORS:  B-19, B-22

AC306322

CONNECTOR: B-108

B-108 (GR)

AC

TRANSMISSION
RANGE SWITCH

2

7

1

8

3

9

4

6

10

5

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-179

STEP 7. Check the harness for an open or short circuit to 
ground between A/T-ECU connector B-22 terminal 15 and 
A/T control solenoid valve assembly connector B-108 
terminal 8.
Q: Is the harness wire in good condition?

YES : Replace the A/T-ECU.
NO :  Repair or replace the harness wire.

16DB564A

COVER

AIR

CLEANER

A/T

CONTROL

UNIT

CONNECTORS:  B-19, B-22

AC306322

CONNECTOR: B-108

B-108 (GR)

AC

TRANSMISSION
RANGE SWITCH

2

7

1

8

3

9

4

6

10

5