Mitsubishi Galant. Manual — part 444

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-243

DIAGNOSIS

STEP 1. Check the engine system.
(1) Refer to GROUP 13A <2.4L Engine>, Diagnosis

−

Symptom Chart

−

Poor acceleration

P.13A-357

, or GROUP

13B <3.0L Engine>, Diagnosis

−

Symptom Chart

−

Poor

acceleration

P.13B-440

.

Q: Is the inspection result good?

YES : Go to Step 2.
NO : Repair or replace the engine component(s).

STEP 2. Check each brake and clutch.
Perform the torque converter stall test. Refer to

P.23A-22

,

Torque Converter Stall Test. Then check for the symptom.

Q: Is the symptom eliminated?

YES : Diagnosis is complete.
NO : Go to Step 3.

STEP 3. Perform the hydraulic pressure test.
Perform the hydraulic pressure test. Refer to

P.23A-23

,

Hydraulic Pressure Test. Then check for the symptom.

Q: Is the symptom eliminated?

YES : Diagnosis is complete.
NO : Go to Step 4.

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

GROUP 23B, Transaxle

P.23B-10

.

(2) Blow compressed air into the each brake oil orifice and

clutch oil orifice of the transaxle case, and check if the each
brake and each clutch piston move and air pressure is
maintained.

Q: Is the air pressure maintained?

YES : Diagnosis is complete.
NO : Go to Step 5.

AC001870

LOW-REVERSE BRAKE
OIL ORIFICE

REVERSE CLUTCH
OIL ORIFICE

OVERDRIVE
CLUTCH
OIL ORIFICE

SECOND BRAKE
OIL ORIFICE

UNDERDRIVE
CLUTCH
OIL ORIFICE

AB

AUTOMATIC TRANSAXLE DIAGNOSIS

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AUTOMATIC TRANSAXLE

23A-244

STEP 5. Check each brake system and clutch system.
(1) Remove the transaxle.
(2) Check the facings for seizure and piston seal ring for

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

P.23B-10

,

Underdrive Clutch and Input Shaft

P.23B-51

, Reverse and

Overdrive Clutch

P.23B-53

. Then check for the symptom.

Q: Is the symptom eliminated?

YES : Diagnosis is complete.
NO : Go to Step 6.

STEP 6. Replace the PCM.

Q: Is the symptom eliminated?

YES : Diagnosis is complete.
NO : Start over at Step 1.

INSPECTION PROCEDURE 14: Vibration

COMMENT
If vibration occurs when driving at constant speed or
when accelerating in 4th gear, abnormal torque
converter clutch pressure or a malfunction of the
engine system, torque converter clutch solenoid,
torque converter or valve body may exist.

TROUBLESHOOTING HINTS (The most likely

causes for this case:)

•

Abnormal torque converter clutch pressure

•

Malfunction of the engine system

•

Malfunction of the torque converter clutch
solenoid

•

Malfunction of the torque converter

•

Malfunction of the valve body

•

Malfunction of the PCM

DIAGNOSIS

REQUIRED SPECIAL TOOL:
MB991502: Scan Tool (MUT-II)

AC001868

REVERSE
CLUTCH

SECOND
BRAKE

LOW-
REVERSE
BRAKE

UNDERDRIVE
CLUTCH

OVERDRIVE CLUTCH

AB

AUTOMATIC TRANSAXLE DIAGNOSIS

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AUTOMATIC TRANSAXLE

23A-245

STEP 1. Using scan tool MB991502, check actuator test
item 06: Torque Converter Clutch Solenoid Valve.

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to "LOCK" (OFF) position before
connecting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to "ON" position.
(3) Set scan tool MB991502 to actuator test mode for item 06:

Torque Converter Clutch Solenoid Valve.

•

An operation sound should be heard from solenoid
valve when the torque converter clutch solenoid valve is
operated.

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

Q: Is the solenoid valve operating properly?

YES : Go to Step 2.
NO : Repair or replace the torque converter clutch solenoid

valve. Refer to GROUP 23B, Valve Body

P.23B-68

.

Then confirm that the symptom is eliminated.

STEP 2. Check the vibration.

Q: Does the vibration occur when the transmission fluid

temperature sensor connector has been disconnected?
YES : Check the engine system. Refer to GROUP 13A

<2.4L Engine>, Diagnosis

−

Symptom Chart

−

Driving

P.13A-22

, or GROUP 13B <3.0L Engine>, Diagnosis

−

Symptom Chart

−

Driving

P.13B-22

. If the

inspection result is not good, diagnose, repair, and/or
replace the engine component(s).

NO : Go to Step 3.

STEP 3. Check the torque converter hydraulic pressure.
Measure the torque converter hydraulic pressure. Then check if
the torque converter hydraulic pressure is within the standard
value. Refer to

P.23A-23

, Hydraulic Pressure Test.

Q: Is the torque converter hydraulic pressure within the

standard value?
YES : Go to Step 4.
NO : Go to Step 5.

AC003081AC

MB991502

DATA LINK
CONNECTOR

AUTOMATIC TRANSAXLE DIAGNOSIS

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AUTOMATIC TRANSAXLE

23A-246

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 : Diagnosis is complete.
NO : Go to Step 6.

STEP 5. 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-68

.

Q: Is the repair possible and the symptom eliminated?

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

symptom. Go to Step 6.

STEP 6. Replace the PCM.

Q: Is the symptom eliminated?

YES : Diagnosis is complete.
NO : Start over at Step 1.

AC001857

AC001860 AB

VALVE
BODY
ASSEMBLY