Mitsubishi Montero Sport (2004+). Manual — part 695

AUTOMATIC TRANSMISSION DIAGNOSIS

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AUTOMATIC TRANSMISSION

23A-345

STEP 6. Replace the transmission oil pump.

Replace the transmission oil pump (Oil pump cannot be
repaired). Refer to GROUP 23B, Transmission

P.23B-19

. Con-

firm that the malfunction symptom is eliminated.
Q: Is the symptom eliminated?

YES : The procedure is complete.
NO : Go to Step 7.

STEP 7. Replace the PCM.
Q: Does the engine crank when the selector lever is placed

in the "P" or "N" position?
YES : The procedure is complete.
NO : Start over at Step 1.

INSPECTION PROCEDURE 2: Does not Move Forward

.

COMMENT
If the engine is idling and the selector lever is shifted
from "N" to "D", "2" or "L" range and the vehicle does
not drive forward then the cause is due to line pres-
sure defect, under drive clutch or valve body mal-
function.

.

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

• Abnormal line pressure

• Malfunction of the underdrive solenoid valve

• Malfunction of the underdrive clutch

• Malfunction of the valve body

• Malfunction of the PCM

AC103774

OIL PUMP

AF

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AUTOMATIC TRANSMISSION

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DIAGNOSIS

Required Special Tool:

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

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

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 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-67

. Then

confirm that the symptom is eliminated.

STEP 2. Check the hydraulic pressure.

Shift the selector lever to the "L" range then measure the
hydraulic pressure of each element in 1st speed to check and
see if each respective hydraulic pressure is within the range of
standard pressure. Refer to

P.23A-26

, Hydraulic Pressure Test.

Q: Is the hydraulic pressure within the standard value?

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

AK303629AB

MB991911

MB991827

MB991824

16-PIN

AUTOMATIC TRANSMISSION DIAGNOSIS

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AUTOMATIC TRANSMISSION

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STEP 3. Check the underdrive clutch system.
(1) Remove the valve body cover and valve body. Refer to

P.23A-453

, Transmission and Transfer Assembly and refer

to GROUP 23B, Transmission

P.23B-19

.

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

clutch oil orifice of the transmission 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 4.
NO : Go to Step 5.

STEP 4. 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-67

.

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 5. Check the underdrive clutch.
(1) Remove the transmission 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, Underdrive
Clutch and Input Shaft

P.23B-63

. 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.

ACX02249AB

UNDERDRIVE
CLUTCH OIL
ORIFICE

AC004272

VALVE BODY ASSEMBLY

AB

AC103774

UNDERDRIVE CLUTCH

AG

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INSPECTION PROCEDURE 3: Does not Move Backward

.

COMMENT
If the vehicle does not move backward when the
selector lever is shifted from "N" to "R" range while
the engine is idling, the cause is probably abnormal
pressure or a malfunction of the reverse clutch,
low-reverse brake, or valve body.

.

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

• 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 PCM

DIAGNOSIS

Required Special Tool:

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

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

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 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-67

. Then

confirm that the symptom is eliminated.

AK303629AB

MB991911

MB991827

MB991824

16-PIN