Mitsubishi 380. Manual — part 422

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-228

STEP 2. Replace the damper clutch control solenoid valve.
Replace the damper clutch control solenoid valve. Refer to
GROUP 23B, Valve Body

P.23B-62

. Then check the symptom.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO : Go to Step 3.

STEP 3. Disassemble and clean the valve body.
Check the O-ring installation bolts for looseness and valve
body for damage. Repair or replace the faulty parts. Refer to
GROUP 23B, Valve Body

P.23B-62

.

Replace the valve body assembly if the damages are thought
to be irreparable. Then check the symptom.

Q: Is the repair possible and the symptom eliminated?

YES : The procedure is complete.
NO : Go to Step 4.

STEP 4. Replace the torque converter assembly.
(1) Remove the transmission.
(2) Replace the torque converter assembly. Refer to GROUP

23B, Transmission

P.23B-13

. Then check the symptom.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO : Start over at Step 1.

DCC
Solenoid
Valve

VALVE BODY
ASSEMBLY

10DB122A

VALVE BODY
ASSEMBLY

10DB117A

AC001857

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-229

INSPECTION PROCEDURE 6: Shift Shock when Shifting from "N" to "D" and Long Delay

.

COMMENT

If abnormal shock or delay of two seconds or more
occurs when the selector lever is shifted from "N" to
"D" range while the engine is idling, the cause is
probably abnormal underdrive clutch pressure or a
malfunction of the underdrive clutch, valve body or
TP sensor.

.

TROUBLESHOOTING HINTS (The most
likely causes for this condition:)

• Abnormal underdrive clutch pressure

• Malfunction of the underdrive solenoid valve

• Malfunction of the underdrive clutch

• Malfunction of the valve body

• Malfunction of the TP sensor

• Malfunction of the A/T-ECU system
• Check RED brake system

Circuit drawings

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

• Refer to component locations GROUP-

70

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 02: Underdrive 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 02: Underdrive Solenoid Valve.

• An audible clicking or buzzing should be heard when

the underdrive solenoid valve is energized.

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

Q: Is the solenoid valve operating properly?

YES : Go to Step 2.
NO : Repair or replace the underdrive solenoid valve.

Refer to GROUP 23B, Valve Body

P.23B-62

. Then

confirm that the symptom is eliminated.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-230

STEP 2. Check when shift shock occurs.

Q: When does the shift shock occur?

When engaging from "N" to "D" : Go to Step 3.
When the vehicle starts moving : Go to Step 6.

STEP 3. Check the hydraulic pressure (for underdrive
clutch).
Measure the hydraulic pressure for underdrive clutch when the
selector lever is shifted from "N" to "D" range. Check if the
hydraulic pressure is within the standard value. Refer to

P.23A-26

, Hydraulic Pressure Test.

Q: Is the hydraulic pressure within the standard value?

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

STEP 4. Check the underdrive clutch system.
(1) Remove the valve body cover and valve body. Refer to

P.23A-304

<F5A5A>, Transmission Assembly and GROUP

23B, Transmission

P.23B-13

.

(2) Blow 108 kPa (15 psi) compressed air into the underdrive

clutch oil orifice of the transmission case, and check if the
underdrive clutch piston moves and air pressure is
maintained in that condition.

Q: Is the air pressure maintained?

YES : Go to Step 8.
NO : Go to Step 5.

STEP 5. Check the underdrive clutch.
(1) Remove the transmission assembly.
(2) Check the facing for seizure and the piston seal ring for

damage and interference with the retainer. Repair or
replace the faulty parts. Refer to GROUP 23B

P.23B-46

,

Underdrive Clutch and Input Shaft. Then check the
symptom.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO : Start over at Step 1.

STEP 6. Check shift shock.

Q: Does shift shock occur?

YES : Go to Step 7.
NO : Go to Step 8.

AC001859

UNDERDRIVE

CLUTCH OIL

ORIFICE

AB

AC001861

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-231

STEP 7. Using diagnostic tool MB991958, check MPI data
list item 13: TP Sensor (main).

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 data reading mode.

• Item 13: TP Sensor (main).

• With the throttle valve in idle position, voltage should

measure between 1100 and 1200 mV.

• With the throttle valve in full-open position, voltage

should measure 4,000 mV or more.

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

Q: Is the measured voltage between 1100 and 1200 mV at

idle, and 4,000 mV or more at the full-open position?
YES : Go to Step 8.
NO : Check the TP sensor. Refer to GROUP13A

,Diagnostic Trouble Code Procedures

13A-17

, DTCs

P0122, P0123: TP Sensor System. Then check the
symptom.

STEP 8. Disassemble and clean the valve body.
Check the O-ring installation bolts for looseness and the valve
body for damage. Repair or replace the faulty parts. Refer to
GROUP 23B, Valve Body

P.23B-62

.

Replace the valve body assembly if the damages are thought
to be irreparable. Then check the symptom.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO : Replace the valve body assembly. Then check the

symptom. Start over at Step 1.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

VALVE BODY
ASSEMBLY

10DB117A