Mitsubishi Eclipse. Manual - part 823

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-301

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 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-74

. 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-28

, Hydraulic Pressure Test.

Q: Is the hydraulic pressure within the standard value?

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

AC303127

AB

MB991911

16-PIN

MB991827

MB991824 

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-302

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

P.23A-423

, Transaxle Assembly and GROUP 23B, 

Transaxle 

P.23B-10

.

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

clutch oil orifice of the transaxle 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-74

.

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 transaxle 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-57

. 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.

AC001859

UNDERDRIVE
CLUTCH OIL
ORIFICE

AB

AC001860 AB

VALVE
BODY
ASSEMBLY

AC001861

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-303

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 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-74

. Then 

confirm that the symptom is eliminated.

AC303127

AB

MB991911

16-PIN

MB991827

MB991824 

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-304

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.23A-28

, 

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

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

STEP 3. Check the hydraulic pressure (for low-reverse 
brake).
Measure the hydraulic pressure for low-reverse brake when the 
selector lever is at the "R" range, and check if the hydraulic 
pressure is within the standard value. Refer to 

P.23A-28

, 

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

YES : Go to Step 4.
NO :  Go to Step 5.

STEP 4. Check the reverse clutch system and low-reverse 
brake system.
(1) Remove the valve body cover and valve body. Refer to 

P.23A-423

, Transaxle Assembly and GROUP 23B, 

Transaxle 

P.23B-10

.

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

clutch oil orifice of the transaxle case. Then check if the 
reverse clutch piston moves and air pressures are 
maintained in that condition. Repeat for the low-reverse 
brake.

Q: Are the reverse clutch, low-reverse brake or both air 

pressures maintained?
YES : Go to Step 5.
NO :  Go to Step 6.

STEP 5. 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-74

.

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 7.

AC001862

REVERSE CLUTCH
OIL ORIFICE

LOW-REVERSE 
BRAKE OIL ORIFICE

AB

AC001860 AB

VALVE
BODY
ASSEMBLY