Mitsubishi 380. Manual - part 408

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-172

STEP 12. Check the harness for an open or short circuit to 
ground between A/T-ECU connector B-21 (terminals 1, 14 
and 2) and A/T control solenoid valve assembly connector 
B-108 (terminals 3, 4 and 5).
Q: Are the harness wires in good condition?

YES : Go to Step 13.
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

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-173

STEP 13. Check the harness for an open or short circuit to 
ground between A/T control solenoid valve assembly 
connector B-108 (terminals 3, 4, 5, and 9) and solenoid 
valve connectors B-108-1, B-108-2 and B-108-3.
Q: Is the harness wire in good condition?

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

AC306322

CONNECTOR: B-108

B-108 (GR)

AC

TRANSMISSION
RANGE SWITCH

2

7

1

8

3

9

4

6

10

5

VALVE BODY
ASSEMBLY

10DB106A

CONNECTORS: B-108-1, B-108-2, B-108-3     

B-108-1

B-108-2

B-108-3

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-174

(P0773): Reduction Solenoid Valve System

.

SOLENOID VALVE SYSTEM CIRCUIT

 Refer to 

P.23A-133

.

.

CIRCUIT OPERATION

 Refer to 

P.23A-133

.

.

DTC SET CONDITIONS

Check Conditions

• Solenoid status: either solid ON or OFF.

• Voltage of battery: 10 volts or more.

Judgement Criteria

• Solenoid voltage: 3 volts or less. (0.3 second)

• If (P0773) is set consecutively four times, the 

transmission is locked into 3rd gear as a fail-safe 
measure, and the "N" range light flashes once 
per second.

.

OBD-II DRIVE CYCLE PATTERN

Start the engine, and keep the vehicle stopped in "P" 
range for 5 seconds.

.

TROUBLESHOOTING HINTS (THE MOST 
LIKELY CAUSES FOR THIS CODE TO BE 
SET ARE:)

• Malfunction of the reduction solenoid valve

• Damaged harness or connector

• Malfunction of the A/T-ECU

Circuit drawings

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

• Refer to component locations GROUP-

70

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-175

DIAGNOSIS

Required Special Tool:

• MB991958: Diagnostic Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

STEP 1. Using diagnostic tool MB991958,

 

check actuator 

test item 05: Reduction Solenoid Valve.

CAUTION

To prevent damage to diagnostic tool MB991958, always 
turn the ignition switch to the "LOCK" (OFF) position 
before connecting or disconnecting diagnostic tool 
MB991958.
(1) Connect diagnostic tool MB991958 to the data link 

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Set diagnostic tool MB991958 to the actuator test mode.

• Item 05: Reduction Solenoid Valve.

• An audible clicking or buzzing should be heard when 

the reduction solenoid valve is energized.

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

Q: Is the solenoid valve operating properly?

YES : It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 

− How to 

Cope with Intermittent Malfunctions 

P.00-14

.

NO :  Go to Step 2.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827