Mitsubishi 380. Manual - part 373

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-32

HYDRAULIC CIRCUIT

M1231008800336

OVERVIEW

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

R N D

   P

10DB150A

  1. REVERSE 

CLUTCH

  2. LOW-REVERSE 

BRAKE

  3. SECOND 

BRAKE

  4. UNDERDRIVE 

CLUTCH

  5. OVERDRIVE 

CLUTCH

  6. RED 

CLUTCH

  7. DIR 

CLUTCH

  8. TORQUE 

CONVERTER 

CLUTCH

  9. FAIL 

SAFE 

VALVE 

A

  10. 

FAIL 

SAFE 

VALVE 

B

  11. 

FAIL 

SAFE 

VALVE 

C

  12. 

SWITCH 

VALVE

  13. 

TRANSMISSION 

FLUID 

COOLER

    14.  TORQUE CONVERTER CLUTCH CONTROL 

VALVE

    15.  LOW-REVERSE PRESSURE CONTROL VALVE
  16. 

SECOND 

PRESSURE 

CONTROL 

VALVE

  17. 

UNDERDRIVE 

PRESSURE 

CONTROL 

VALVE

  18. 

OVERDRIVE 

PRESSURE 

CONTROL 

VALVE

    19.  RED PRESSURE CONTROL VALVE 
    20.  TORQUE CONVERTER CLUTCH SOLENOID 

VALVE 

  21. 

LOW-REVERSE 

SOLENOID 

VALVE 

    22.  SECOND SOLENOID VALVE 
    23.  UNDERDRIVE SOLENOID VALVE 
  24. 

OVERDRIVE 

SOLENOID 

VALVE 

    25.  RED SOLENOID VALVE
    26.  TORQUE CONVERTER PRESSURE 

CONTROL VALVE 

  27. 

REGULATOR 

VALVE

  28. 

MANUAL 

VALVE 

  29. 

OIL 

STRAINER

  30. 

OIL 

FILTER

  31. 

OIL 

PUMP

32. OIL FILTER
33. RELIEF VALVE
34. OIL PAN

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-33

LINE PRESSURE ADJUSTMENT

M1231001700361

1. Drain the transmission fluid. 

NOTE: The hydraulic pressure test must be performed 
before attempting any adjustments.

2. Remove the valve body cover.

3. Turn the adjusting screw shown in the illustration to adjust 

the line pressure to the standard value in "D" range 1st or 
2nd gear. The pressure increases when the screw is turned 
counterclockwise approximately 35 kPa for each turn.

NOTE: When adjusting the line pressure, adjust to the mid-
dle of the standard value range.

Standard value: 980 

− 1050 kPa

4. Install the valve body cover. Pour in the standard volume of 

automatic transmission fluid.

5. Repeat the hydraulic pressure test. (Refer to 

P.23A-26

). 

Readjust the line pressure if necessary.

AC006153AB

ADJUSTING
SCREW

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-34

DIAGNOSTIC TROUBLE CODE CHART

M1231007900330

CAUTION

During diagnosis, a DTC code associated with 
other system may be set when the ignition switch 
is turned on with connector(s) disconnected. On 
completion, confirm all systems for DTC code(s). 
If DTC code(s) are set, erase them all.

NOTE: The A/T diagnostic trouble codes are the codes which are set when item "A/T" is selected on 
diagnostic tool MB991958 (MUT-III sub assembly). However, the some codes above indicate failure in the 
MPI system.

A/T DTC 
NO.

DIAGNOSIS ITEM

REFERENCE 
PAGE

P0713

Transmission fluid temperature sensor system

Open circuit

P.23A-36

P0712

Short circuit

P.23A-47

P0715

Input shaft speed sensor system

Short circuit/open circuit

P.23A-55

P0720

Output shaft speed sensor system

Short circuit/open circuit

P.23A-72

−

Stoplamp switch system

Short circuit

P.23A-89

P0705

Transmission range switch system

Open circuit

P.23A-97

Short circuit

P.23A-119

P0753

Low-reverse solenoid valve system

Short circuit/open circuit

P.23A-133

P0758

Underdrive solenoid valve system

Short circuit/open circuit

P.23A-144

P0763

Second solenoid valve system

Short circuit/open circuit

P.23A-154

P0768

Overdrive solenoid valve system

Short circuit/open circuit

P.23A-164

P0773

Reduction (RED) solenoid valve system

Short circuit/open circuit

P.23A-174

P0743

Damper clutch  control (DCC) solenoid valve 
system

Short circuit/open circuit

P.23A-185

P0731

1st gear incorrect ratio

P.23A-196

P0732

2nd gear incorrect ratio

P.23A-196

P0733

3rd gear incorrect ratio

P.23A-196

P0734

4th gear incorrect ratio

P.23A-196

P0735

5th gear incorrect ratio

P.23A-196

P0736

Reverse gear incorrect ratio

P.23A-196

P0741

Damper clutch control (DCC) system

Defective system

P.23A-201

P0742

Clutch stuck on

P.23A-204

P1751

A/T control relay system

Short circuit to ground/open 
circuit

P.23A-207

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-35

SYMPTOM CHART 

M1231008000277

CAUTION

During diagnosis, a DTC code associated with 
other system may be set when the ignition switch 
is turned on with connector(s) disconnected. On 
completion, confirm all systems for DTC code(s). 
If DTC code(s) are set, erase them all.

SYMPTOM

INSPECTION 
PROCEDURE NO.

REFERENCE 
PAGE

Communication with diagnostic 
tool is not possible

Communication with all systems 
is impossible

-

Group 13B 
Symptom 
Procedures 

13A-539

.

Communication with the 
A/T-ECU only is impossible

-

Group 13B 
Symptom 
Procedures 

13A-541

.

Driving impossible

Engine does not start

1

P.23A-218

Does not move forward

2

P.23A-220

Does not move backward

3

P.23A-223

Does not move (forward and 
backward)

4

P.23A-226

Malfunction when moving 
selector into gear

Engine stalls when moving 
selector lever from "N" to "D" or 
"N" to "R"

5

P.23A-227

Shift shock when shifting from 
"N" to "D" and long delay

6

P.23A-229

Shift shock when shifting from 
"N" to "R" and long delay 

7

P.23A-232

Shift shock when shifting from 
"N" to "D" and "N" to "R" and 
long delay 

8

P.23A-235

Malfunction when shifting

Shift shock and slipping

9

P.23A-236

Does not shift properly

Early or late shifting in all gears 10

P.23A-239

Early or late shifting in some 
gears

11

P.23A-242

Does not shift

No diagnostic trouble codes

12

P.23A-244

Malfunction while driving

Poor acceleration

13

P.23A-248

Vibration

14

P.23A-250

Shift switch assembly system

15

P.23A-252

Shift position indicator light system <Vehicles with sport mode>

16

P.23A-269