Mitsubishi Galant 9G. Manual — part 554

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-387

<F4A4B> or

P.23A-395

<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

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-295

STEP 7. Using scan tool MB991958, check data list item 11:
TP Sensor.

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 data reading mode.

• Item 11: TP Sensor.

• With the throttle valve in idle position, voltage should

measure between 300 and 700 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 300 and 700 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 <2.4L

Engine>, Diagnostic Trouble Code Procedures

P.13A-159

,

P.13A-169

, DTCs P0122, P0123: TP

Sensor System or refer to GROUP13B <3.8L
Engine>, Diagnostic Trouble Code Procedures

P.13B-162

,

P.13B-172

, 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-80

.

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. Go to Step 9.

STEP 9. Replace the PCM.
Q: Is the symptom eliminated?

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

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC001860 AB

VALVE
BODY
ASSEMBLY

AUTOMATIC TRANSAXLE DIAGNOSIS

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AUTOMATIC TRANSAXLE

23A-296

INSPECTION PROCEDURE 7: Shift Shock when Shifting from "N" to "R" and Long Delay

.

COMMENT

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

.

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

• Abnormal reverse clutch pressure

• Abnormal low-reverse brake pressure

• Malfunction of the low-reverse solenoid valve

• Malfunction of the reverse clutch

• Malfunction of the low-reverse brake

• 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 01: Low-Reverse 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 01: Low-Reverse Solenoid Valve.

• An audible clicking or buzzing should be heard when

the low-reverse 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 low-reverse solenoid valve.

Refer to GROUP 23B, Valve Body

P.23B-80

. 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 "R" : Go to Step 3.
When the vehicle starts moving : Go to Step 7.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-297

STEP 3. Check the hydraulic pressure (for reverse clutch).
Measure the hydraulic pressure for reverse clutch when the
selector lever is at the "R" range. Check if the hydraulic pres-
sure 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 9.

STEP 4. Check the hydraulic pressure (for low-reverse
brake).
Measure the hydraulic pressure for low-reverse brake when the
selector lever is at the "R" range. Check if the hydraulic pres-
sure 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 5.
NO : Go to Step 9.

STEP 5. Check the reverse clutch system and low-reverse
brake system.
(1) Remove the valve body cover and valve body. Refer to

P.23A-387

<F4A4B> or

P.23A-395

<F4A5A>, Transaxle

Assembly and GROUP 23B, Transaxle

P.23B-10

.

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

clutch oil orifice of the transaxle case, and check if the
reverse clutch piston moves and air pressures are
maintained in that condition. Repeat for the low-reverse
brake.

Q: Are both air pressures maintained?

YES : Go to Step 6.
NO : Go to Step 9.

STEP 6. Check the reverse clutch and low-reverse brake.
(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, Transaxle

P.23B-10

, Reverse and Overdrive Clutch

P.23B-62

. Then

Retest the system.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO : Go to Step 10.

AC001862

REVERSE CLUTCH
OIL ORIFICE

LOW-REVERSE
BRAKE OIL ORIFICE

AB

AC001863 AB

LOW-REVERSE BRAKE

REVERSE CLUTCH