Mitsubishi Galant (2004+). Manual - part 685

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-291

STEP 4. Replace the oil pump.

(1) Remove the transaxle.
(2) Replace the oil pump (Oil pump cannot be repaired). Refer 

to GROUP 23B, Transaxle 

P.23B-10

. Then check the 

symptom.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO :  Go to Step 5.

STEP 5. Replace the PCM.
Q: Is the symptom eliminated?

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

INSPECTION PROCEDURE 5: Engine Stalls when Moving Selector Lever from "N" to "D" or "N" to "R"

.

COMMENT
If the engine stalls when the selector lever is shifted 
from "N" to "D" or "R" range while the engine is idling, 
the cause is probably a malfunction of the engine 
system, torque converter clutch solenoid valve, valve 
body or torque converter (torque converter clutch 
malfunction).

.

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

• Malfunction of the engine system

• Malfunction of the torque converter clutch sole-

noid

• Malfunction of the valve body

• Malfunction of the torque converter (Malfunction 

of the torque converter clutch)

• Malfunction of the PCM

DIAGNOSIS

STEP 1. Check the engine system.

Refer to GROUP 13A <2.4L Engine>, Diagnosis 

− Trouble 

Symptom Chart 

− When the engine is hot, it stalls at idle 

P.13A-38

.

Refer to GROUP 13B <3.8L Engine>, Diagnosis 

− Trouble 

Symptom Chart 

− When the engine is hot, it stalls at idle 

P.13B-37

.

Q: Is the inspection result good?

YES : Go to Step 2.
NO :  Repair or replace the engine components.

AC001858

AUTOMATIC TRANSAXLE DIAGNOSIS

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AUTOMATIC TRANSAXLE

23A-292

STEP 2. Replace the torque converter clutch solenoid 
valve.

Replace the torque converter clutch solenoid valve. Refer to 
GROUP 23B, Valve Body 

P.23B-79

. 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-79

.

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 transaxle.
(2) Replace the torque converter assembly. Refer to GROUP 

23B, Transaxle 

P.23B-10

. Then check the symptom.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO :  Go to Step 5.

STEP 5. Replace the PCM.
Q: Is the symptom eliminated?

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

AC001866

AC001860 AB

VALVE
BODY
ASSEMBLY

AC001857

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-293

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 PCM

DIAGNOSIS

Required Special Tool:

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

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

STEP 1. Using scan tool MB991958, check actuator test 
item 02: Underdrive Solenoid Valve.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958. 
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.

(3) Set scan 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-79

. Then 

confirm that the symptom is eliminated.

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.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-294

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-29

, 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-392

 <F4A4B> or 

P.23A-400

 <F4A5A>, Transaxle 

Assembly and GROUP 23B, Transaxle 

P.23B-10

.

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

clutch oil orifice of the transaxle 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 transaxle 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-60

, 

Underdrive Clutch and Input Shaft. Then check the 
symptom.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO :  Go to Step 9.

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