Mitsubishi Galant. Manual — part 441

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-231

STEP 8. Using scan tool MB991502, check data list item 11:
Throttle position sensor.

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 data reading mode for item 11:

Throttle Position Sensor.

•

With the throttle valve in idle position, voltage should be
between 535 and 735 mV.

•

With the throttle valve in full-open position, voltage
should be between 4,500 and 5,500 mV.

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

Q: Is the sensor operating properly?

YES : Go to Step 9.
NO : Check the throttle position sensor. Refer to

P.23A-39

,

P.23A-48

,

P.23A-56

, code number 11, 12, 14: Throttle

Position Sensor System. Then check the symptom.

STEP 9. 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 10.

STEP 10. Replace the PCM.

Q: Is the symptom eliminated?

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

INSPECTION PROCEDURE 8: Shift Shocks when Shifting from "N" to "D," "N" to "R" and Long Delay

COMMENT
If abnormal shocks or delay of two seconds or more
occur when the selector lever is shifted from "N" to
"D" range and from "N" to "R" range while the engine
is idling, the cause is probably abnormal line
pressure or a malfunction of the oil pump or valve
body.

TROUBLESHOOTING HINTS (The most likely

causes for this code to be set:)

•

Abnormal line pressure

•

Malfunction of the oil pump

•

Malfunction of the valve body

•

Malfunction of the PCM

AC003081AC

MB991502

DATA LINK
CONNECTOR

AC001860 AB

VALVE
BODY
ASSEMBLY

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-232

DIAGNOSIS

STEP 1. Check the hydraulic pressure.
(1) Measure the hydraulic pressure of each element when the

transmission is in 1st, 2nd or reverse. Check if each
hydraulic pressure is within the standard value. Refer to

P.23A-23

, Hydraulic Pressure Test.

(2) If some elements are within the standard value and some

are not, recheck the symptom.

Q: Are all hydraulic pressures within the standard value?

YES : Go to Step 3.
NO : Go to Step 2.

STEP 2. Adjust line pressure.
Adjust line pressure. Refer to

P.23A-37

, Line Pressure

Adjustment. Then check the symptom.

Q: Is the symptom eliminated?

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

STEP 3. Check when shift shocks occur.

Q: When the shift shocks occur?

When engaging from N to D and N to R : Go to Step 4.
When the vehicle starts moving : Go to Step 5.

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

STEP 5. Disassemble and clean the valve body.
Check the installation bolts for looseness and the O-ring, valve
and 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.

AC001865

AC001860 AB

VALVE
BODY
ASSEMBLY

AUTOMATIC TRANSAXLE DIAGNOSIS

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AUTOMATIC TRANSAXLE

23A-233

STEP 6. Replace the PCM.

Q: Is the symptom eliminated?

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

INSPECTION PROCEDURE 9: Shift Shocks and Slipping

COMMENT
If shift shocks when driving due to upshifting or
downshifting and the transaxle speed becomes
higher than the engine speed, the cause is probably
abnormal line pressure or a malfunction of a solenoid
valve, oil pump, valve body or of a brake or clutch.

TROUBLESHOOTING HINTS (The most likely

causes for this code to be set:)

•

Abnormal line pressure

•

Malfunction of each solenoid valve

•

Malfunction of the oil pump

•

Malfunction of the valve body

•

Malfunction of the each brake or each clutch

•

Malfunction of the PCM

DIAGNOSIS

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

STEP 1. Using scan tool MB991502, check actuator test.

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 following

items.

a. Item 01: Low-reverse solenoid valve
b. Item 02: Underdrive solenoid valve

c. Item 03: Second solenoid valve

d. Item 04: Overdrive solenoid valve

•

An operation sound should be heard from solenoid
valve when solenoid valve is operated.

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

Q: Are the solenoid valves operating properly?

YES : Go to Step 2.
NO : Repair or replace the solenoid valves. Refer to

GROUP 23B, Valve Body

P.23B-68

. Then confirm

that the symptom is eliminated.

STEP 2. Adjust the line pressure.
Adjust the line pressure. Refer to

P.23A-37

, Line Pressure

Adjustment. Then check the symptom.

Q: Is the symptom eliminated?

YES : Go to Step 3.
NO : Go to Step 4.

AC003081AC

MB991502

DATA LINK
CONNECTOR

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-234

STEP 3. Check each brake and clutch.
(1) Remove the transaxle.
(2) Check the facing 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 4. Replace the oil pump.
(1) Remove the transaxle.
(2) Replace the oil pump. (Oil pump can not be repaired). 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 5.

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.

INSPECTION PROCEDURE 10: All Points (Early or Late Shift Points)

COMMENT
If all shift points are early or late while driving, the
cause is probably a malfunction of the output shaft

speed sensor, throttle position sensor or a solenoid
valve.

AC001868

REVERSE
CLUTCH

SECOND
BRAKE

LOW-
REVERSE
BRAKE

UNDERDRIVE
CLUTCH

OVERDRIVE CLUTCH

AB

AC001865

AC001860 AB

VALVE
BODY
ASSEMBLY