Mitsubishi Montero (2004+). Manual - part 934

AUTOMATIC TRANSMISSION DIAGNOSIS

TSB Revision

AUTOMATIC TRANSMISSION

23A-311

STEP 2. 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-63

.

Replace the valve body assembly if the damages are thought 
to be irreparable. Then retest the system.
Q: Is the repair possible and the symptom eliminated?

YES : The procedure is complete.
NO :  Go to Step 4.

STEP 3. Check the transmission power train components.
Disassemble the transmission and check the planetary carrier 
and output shaft, etc. Repair or replace the damaged parts. 
Refer to GROUP 23B, Transmission 

P.23B-14

, Low-Reverse 

Annulus Gear 

P.23B-55

. Then check the symptom.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO :  Go to Step 5.

STEP 4. Replace the transmission oil pump.
(1) Remove the transmission.
(2) Replace the transmission oil pump (Oil pump cannot be 

repaired). Refer to GROUP 23B, Transmission 

P.23B-14

. 

Then check the symptom.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO :  Go to Step 5.

STEP 5. Replace the PCM.
Q: Is the symptom eliminated?

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

ACX02161AD

VALVE BODY ASSEMBLY

AC204883AJ

PLANETARY
CARRIER

DIRECT
PLANETARY
CARRIER

AC204883 AD

AUTOMATIC TRANSMISSION DIAGNOSIS

TSB Revision

AUTOMATIC TRANSMISSION

23A-312

INSPECTION PROCEDURE 5: Engine Stalls when Moving Selector Lever from "N" to "D" or "N" to "R"

.

COMMENT
If the engine stalls when the selector lever is shifted 
from "N" to "D" or "R" range while the engine is idling, 
the cause is probably a malfunction of the engine 
system, torque converter clutch solenoid valve, valve 
body or torque converter (torque converter clutch 
malfunction).

.

TROUBLESHOOTING HINTS (THE MOST LIKELY 
CAUSES FOR THIS CASE:)

• Malfunction of the engine system

• Malfunction of the torque converter clutch sole-

noid

• Malfunction of the valve body

• Malfunction of the torque converter (Malfunction 

of the torque converter clutch)

• Malfunction of the PCM

DIAGNOSIS

STEP 1. Check the engine system.
Refer to GROUP 13A, Diagnosis 

− Trouble Symptom Chart − 

When the engine is hot, it stalls at idle 

P.13A-30

.

Q: Is the inspection result good?

YES : Go to Step 2.
NO :  Repair or replace the engine components.

STEP 2. Replace the torque converter clutch solenoid 
valve.
Replace the torque converter clutch solenoid valve. Refer to 
GROUP 23B, Valve Body 

P.23B-63

. Then check the symptom.

Q: Is the symptom eliminated?

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

STEP 3. 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-63

.

Replace the valve body assembly if the damages are thought 
to be irreparable. Then check the symptom.
Q: Is the repair possible and the symptom eliminated?

YES : The procedure is complete.
NO :  Go to Step 4.

ACX02161AE

ACX02161AD

VALVE BODY ASSEMBLY

AUTOMATIC TRANSMISSION DIAGNOSIS

TSB Revision

AUTOMATIC TRANSMISSION

23A-313

STEP 4. Replace the torque converter assembly.
(1) Remove the transmission.
(2) Replace the torque converter assembly. Refer to GROUP 

23B, Transmission 

P.23B-14

. Then check the symptom.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO :  Go to Step 5.

STEP 5. Replace the PCM.
Q: Is the symptom eliminated?

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

INSPECTION PROCEDURE 6: Shift Shock when Shifting from "N" to "D" and Long Delay

.

COMMENT
If abnormal shock or delay of two seconds or more 
occurs when the selector lever is shifted from "N" to 
"D" range while the engine is idling, the cause is 
probably abnormal underdrive clutch pressure or a 
malfunction of the underdrive clutch, valve body or 
APP sensor.

.

TROUBLESHOOTING HINTS (THE MOST LIKELY 
CAUSES FOR THIS CASE:)

• Abnormal underdrive clutch pressure

• Malfunction of the underdrive solenoid valve

• Malfunction of the underdrive clutch

• Malfunction of the valve body

• Malfunction of the APP 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

• MB991911: MUT-III Main Harness B

AC204883 AE

AUTOMATIC TRANSMISSION DIAGNOSIS

TSB Revision

AUTOMATIC TRANSMISSION

23A-314

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 the 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-63

. 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 D : Go to Step 3.
When the vehicle starts moving : Go to Step 6.

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-26

, Hydraulic Pressure Test.

Q: Is the hydraulic pressure within the standard value?

YES : Go to Step 4.
NO :  Go to Step 8.

AC307591 AC

MB991911

MB991824

MB991827

AC307591

DATA LINK

CONNECTOR