Mitsubishi Montero (2002-2004). Manual - part 973

SYMPTOM PROCEDURES <AUTOMATIC TRANSMISSION>

TSB Revision

SYMPTOM PROCEDURES

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STEP 3. Check the engine.
Refer to GROUP 13A, Diagnosis 

− Trouble Symptom Chart − 

Starting 

P.13Ab-26

.

Q: Is the inspection result good?

YES : Go to Step 4.
NO :  Repair or replace the appropriate engine 

components.

STEP 4. Check the torque converter.
(1) Remove the transmission.
(2) Turn the torque converter and check for a binding or 

sticking condition. Check the ring gear for damaged or 
missing teeth.
NOTE: Since the torque converter drives the oil pump, turn-
ing the torque converter also checks for a binding oil pump. 
If either of these components are damaged the Transmis-
sion will need to be removed for inspection.

Q: Does the torque converter turn freely without any 

missing or damaged teeth?
YES : Go to Step 5.
NO :  Replace the torque converter.

STEP 5. Repair or replace the starter.
Q: Is the symptom eliminated?

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

STEP 6. Replace the oil pump.
Replace the oil pump (Oil pump cannot be repaired). Refer to 
GROUP 23B, Transmission 

P.23B-18

. Confirm that the mal-

function 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.

AC204883 AE

AC204883AI

SYMPTOM PROCEDURES <AUTOMATIC TRANSMISSION>

TSB Revision

SYMPTOM PROCEDURES

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INSPECTION PROCEDURE 2: Does not Move Forward

.

COMMENT
If the engine is idling and the selector lever is shifted 
from "N" to "D" range and the vehicle does not drive 
forward then the cause is due to line pressure defect, 
under drive clutch or valve body malfunction.

.

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

DIAGNOSIS

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, check actuator test 
item 02: Underdrive Solenoid Valve.

CAUTION

To prevent damage to scan tool MB991502, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502. 
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991502 to actuator test mode for 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-80

. Then 

confirm that the symptom is eliminated.

STEP 2. Check the hydraulic pressure.
Shift the selector lever to the sport mode (1st gear) then mea-
sure 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.23Ab-15

, Hydraulic 

Pressure Test.
Q: Is the hydraulic pressure within the standard value?

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

ACX01539AD

MB991502

16-PIN

SYMPTOM PROCEDURES <AUTOMATIC TRANSMISSION>

TSB Revision

SYMPTOM PROCEDURES

23Ad-5

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

P.23Aa-37

, Transmission and Transfer Assembly and refer 

to GROUP 23B, Transmission 

P.23B-18

.

(2) Blow108 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-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 :  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-76

. 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

ACX02161AD

VALVE BODY ASSEMBLY

AC204883 AB

SYMPTOM PROCEDURES <AUTOMATIC TRANSMISSION>

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SYMPTOM PROCEDURES

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INSPECTION PROCEDURE 3: Does not Move Backward

.

COMMENT
If the vehicle does not 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:

• MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, check actuator test 
item 01: Low-Reverse Solenoid Valve.

CAUTION

To prevent damage to scan tool MB991502, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502. 
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991502 to actuator test mode for 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 the hydraulic pressure (for reverse clutch).
Measure the hydraulic pressure for reverse clutch when the 
selector lever is at the "R" range, and check if the hydraulic 
pressure is within the standard value. Refer to 

P.23Ab-15

, 

Hydraulic Pressure Test.
Q: Is the hydraulic pressure within the standard value?

YES : Go to Step 3.
NO :  Go to Step 5.

ACX01539AD

MB991502

16-PIN