Mitsubishi Galant (2004+). Manual - part 687

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-299

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

COMMENT
If abnormal shock or delay of two seconds or more
occurs when the selector lever is moved from "N" to
"D" range or 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 condition:)

• Abnormal line pressure

• Malfunction of the oil pump

• Malfunction of the valve body

• Malfunction of the PCM

DIAGNOSIS

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

transaxle is in 1st, 2nd or reverse. Check if each hydraulic

pressure is within the standard value. Refer to

P.23A-29

Hydraulic Pressure Test.

(2) If some elements pressures 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-42

, Line Pressure Adjust-

ment. Then check the symptom.
Q: Is the symptom eliminated?

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

STEP 3. Check when shift shock occurs.
Q: When does the shift shock 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 : The procedure is complete.
NO : Go to Step 6.

AC001865

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-300

STEP 5. Disassemble and clean the valve body.

Check the installation bolts for looseness and the O-ring,
valves 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 symptom eliminated?

YES : The procedure is complete.
NO : Go to Step 6.

STEP 6. Replace the PCM.
Q: Is the symptom eliminated?

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

INSPECTION PROCEDURE 9: Shift Shock and Slipping

COMMENT
If shift shock when driving is due to upshifting or
downshifting and the transaxle speed become higher
than the engine speed, the cause is probably abnor-
mal 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 conditon:)

• Abnormal line pressure

• Malfunction of each solenoid valve

• Malfunction of the oil pump

• Malfunction of the valve body

• Malfunction of each brake or each clutch

• 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

AC001860 AB

VALVE
BODY
ASSEMBLY

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-301

STEP 1. Using scan tool MB991958, check actuator test.

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 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 audible clicking or buzzing should be heard when

the solenoid valves are energized.

(4) Turn the ignition switch to the "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-79

. Then confirm

that the symptom is eliminated.