Mitsubishi Colt Ralliart. Manual - part 193

TROUBLESHOOTING <CVT>

CVT

23A-115

INSPECTION PROCEDURES FOR 
TROUBLE SYMPTOM

Inspection Procedure 2: Driving Not Possible (Engine Not Started)

COMMENTS ON TROUBLE SYMPTOM

If the engine does not start when the selector lever is 
in "P" or "N" position, the cause is probably a mal-
function of inhibitor switch system, transmission con-
trol cable or engine system.

PROBABLE CAUSES

• Malfunction of inhibitor switch

• Malfunction of transmission control cable assem-

bly

• Malfunction of engine system

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code
Either of diagnosis codes 51 or 52 is set, inhibitor 
switch is defective.

Q: Are diagnosis codes 51 or 52 output?

YES : 

Refer to diagnosis code 51, 52: Inhibitor 

switch system 

P.23A-97

.

NO : 

Go to Step 2.

STEP 2. Transmission control cable check.
Check the transmission control cable.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair or replace the transmission control 
cable (Refer to 

P.23A-146

).

STEP 3. Engine system check.
Refer to GROUP 13A 

− Troubleshooting, Inspection 

Chart for Trouble Symptoms 

P.13A-231

.

Q: Is the check result normal?

YES : 

The inspection is complete.

NO : 

Check for the relevant trouble symptom.

Inspection Procedure 3: Driving Not Possible (Vehicle Not Moved)

COMMENTS ON TROUBLE SYMPTOM

If the vehicle does not move when the selector lever 
is moved from the N to D, or from N to R with the 
engine idling, the oil pump or the valve body may be 
defective.

PROBABLE CAUSES

• Malfunction of inhibitor switch system

• Malfunction of transmission control cable assem-

bly

• Malfunction of line pressure control solenoid 

valve

• Malfunction of clutch pressure control solenoid 

valve

• Malfunction of oil pump

• Malfunction of forward clutch

• Malfunction of reverse brake

• Malfunction of valve body assembly

• Malfunction of engine system

• Faulty CVT power train system

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code
Either of diagnosis codes 51 or 52 is set, inhibitor 
switch is defective.

Q: Are diagnosis codes 51 or 52 output?

YES : 

Refer to diagnosis code 51, 52: Inhibitor 

switch system 

P.23A-97

.

NO : 

Go to Step 2.

STEP 2. M.U.T.-III actuator test
Item 01: Line pressure control solenoid valve

OK: Operating sound can be heard.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Replace the CVT assembly.

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Index

Group

TOC

TROUBLESHOOTING <CVT>

CVT

23A-116

STEP 3. M.U.T.-III actuator test
Item 04: Clutch pressure control solenoid valve

OK: Operating sound can be heard.

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Refer to code No.34, 38: Clutch pressure 
control solenoid valve system 

P.23A-90

.

STEP 4. Hydraulic pressure test.
Measure the following fluid pressures (Refer to 

P.23A-140

).

a. Forward clutch pressure
b. Reverse brake pressure

c. Line pressure

OK: Refer to 

P.23A-140

.

Q: Is the check result normal?

YES : 

Go to Step 9

NO <"NG" for all items> : 

Replace the CVT 

assembly.

NO <"NG" for both "a" and "b"> : 

Go to Step 5.

NO <"NG" for either "a" or "b"> : 

Go to Step 7.

STEP 5. Replace the engine-CVT-ECU and then 
recheck the symptom.
(1) Replace the engine-CVT-ECU.
(2) Test drive the vehicle.
(3) Check if the symptom.

Q: Does a malfunction take place again?

YES : 

Go to Step 6.

NO : 

The inspection is complete.

STEP 6. Disassemble, clean and assemble the 
valve body assembly.
Check the mounting bolts for looseness, and the 
O-ring, solenoid valve and valve body for damage.

Q: Is the check result normal?

YES : 

The inspection is complete.

NO : 

Replace the valve body assembly.

STEP 7. Check the forward clutch system and 
reverse brake system.
(1) Remove the transmission assembly, the valve 

body cover and the valve body assembly.

(2) Blow air into the forward clutch and the reverse 

brake oil holes on the transmission case. Check 
that the piston moves and the air pressure is 
maintained.

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Go to Step 8.

STEP 8. Check the forward clutch system and 
reverse brake system.
Check the facing for seizure and the piston seal ring 
for damage and interference with the retainer (Refer 
to GROUP 23B - Forward Clutch 

P.23B-31

 or 

Reverse Brake 

P.23B-34

).

Q: Is the check result normal?

YES : 

The inspection is complete.

NO : 

Repair or replace the forward clutch and the 
reverse brake.

STEP 9. Retest the system.
(1) Test drive the vehicle.
(2) Check the trouble symptom again.

Q: Does a malfunction take place again?

YES : 

Replace the CVT assembly.

NO : 

The inspection is complete.

Main

Index

Group

TOC

TROUBLESHOOTING <CVT>

CVT

23A-117

Inspection Procedure 4: Fault at Vehicle Start (Engine Stall During Shift)

COMMENTS ON TROUBLE SYMPTOM

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, damper clutch control solenoid valve, valve 
body or torque converter.

PROBABLE CAUSES

• Malfunction of engine system

• Malfunction of damper clutch control solenoid 

valve

• Malfunction of valve body assembly

• Malfunction of torque converter

• Malfunction of engine-CVT-ECU

DIAGNOSIS PROCEDURE

STEP 1. Engine system check
Refer to GROUP 13A 

− Troubleshooting, Inspection 

Chart for Trouble Symptoms 

P.13A-231

.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Check for the relevant trouble symptom.

STEP 2. M.U.T.-III actuator test
Item 03: Damper clutch control solenoid valve

OK: Operating sound can be heard.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Refer to code No.33, 37: Damper clutch 
control solenoid valve system 

P.23A-86

.

STEP 3. Hydraulic pressure test.
Measure the torque converter hydraulic pressure 
(Refer to 

P.23A-140

).

OK: Refer to 

P.23A-140

.

Q: Is the check result normal?

YES : 

Replace the torque converter.

NO : 

Go to Step 4.

STEP 4. Disassemble, clean and assemble the 
valve body assembly.
Check the mounting bolts for looseness, and the 
O-ring, solenoid valve and valve body for damage.

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Replace the valve body assembly.

STEP 5. Retest the system.
(1) Test drive the vehicle.
(2) Check the trouble symptom again.

Q: Does a malfunction take place again?

YES : 

Replace the engine-CVT-ECU.

NO : 

The inspection is complete.

Inspection Procedure 5: Fault at Vehicle Start (Shift Shock N to D, N to R)

COMMENTS ON TROUBLE SYMPTOM

If harsh shifting is created when the selector lever is 
moved from the N to D, or from N to R with the 
engine idling, the clutch fluid pressure circuit, the for-
ward clutch or the valve body may be defective.

PROBABLE CAUSES

• Malfunction of line pressure control solenoid 

valve

• Malfunction of clutch pressure control solenoid 

valve

• Malfunction of clutch pressure hydraulic circuit

• Malfunction of forward clutch

• Malfunction of reverse brake

• Malfunction of valve body assembly

• Malfunction of engine-CVT-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III actuator test
Item 01: Line pressure control solenoid valve

OK: Operating sound can be heard.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Replace the CVT assembly.

Main

Index

Group

TOC

TROUBLESHOOTING <CVT>

CVT

23A-118

STEP 2. M.U.T.-III actuator test
Item 04: Clutch pressure control solenoid valve

OK: Operating sound can be heard.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Refer to code No.34, 38: Clutch pressure 
control solenoid valve system 

P.23A-90

.

STEP 3. Hydraulic pressure test.
Measure the following fluid pressures (Refer to 

P.23A-140

).

a. Forward clutch pressure
b. Reverse brake pressure

c. Line pressure

OK: Refer to 

P.23A-140

.

Q: Is the check result normal?

YES : 

Go to Step 8.

NO <"NG" for all items> : 

Replace the CVT 

assembly.

NO <"NG" for both "a" and "b"> : 

Go to Step 4.

NO <"NG" for either "a" or "b"> : 

Go to Step 6.

STEP 4. Replace the engine-CVT-ECU and then 
recheck the symptom.
(1) Replace the engine-CVT-ECU.
(2) Test drive the vehicle.
(3) Check the trouble symptom again.

Q: Does a malfunction take place again?

YES : 

Go to Step 5.

NO : 

The inspection is complete.

STEP 5. Disassemble, clean and assemble the 
valve body assembly.
Check the mounting bolts for looseness, and the 
O-ring, solenoid valve and valve body for damage.

Q: Is the check result normal?

YES : 

The inspection is complete.

NO : 

Replace the valve body assembly.

STEP 6. Check the forward clutch system and 
reverse brake system.
(1) Remove the transmission assembly, the valve 

body cover and the valve body assembly.

(2) Blow air into the forward clutch and the reverse 

brake oil holes on the transmission case. Check 
that the piston moves and the air pressure is 
maintained.

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Go to Step 7.

STEP 7. Check the forward clutch and reverse 
brake.
Check the facing for seizure and the piston seal ring 
for damage and interference with the retainer (Refer 
to GROUP 23B - Forward Clutch 

P.23B-31

 or 

Reverse Brake 

P.23B-34

).

Q: Is the check result normal?

YES : 

The inspection is complete.

NO : 

Repair or replace the forward clutch and the 
reverse brake.

STEP 8. Retest the system.
(1) Test drive the vehicle.
(2) Check the trouble symptom again.

Q: Does a malfunction take place again?

YES : 

Replace the CVT assembly.

NO : 

The inspection is complete.

Main

Index

Group

TOC