Mitsubishi Galant (2004+). Manual - part 683

AUTOMATIC TRANSAXLE DIAGNOSIS

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AUTOMATIC TRANSAXLE

23A-283

SYMPTOM PROCEDURES

INSPECTION PROCEDURE 1: Engine does not Crank

COMMENT
If the engine does not crank when the selector lever
is placed in the "P" or "N" position, the cause is prob-
ably a malfunction of the transmission range switch
system, transaxle control cable assembly, engine
system, torque converter or transaxle oil pump.

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

• Malfunction of the transmission range switch

• Malfunction of the transaxle control cable assem-

bly

• Malfunction of the engine system

• Malfunction of the torque converter

• Malfunction of the transaxle oil pump

• Malfunction of the PCM

DIAGNOSIS

Required Special Tool:

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

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

STEP 1. Using scan tool MB991958, read the A/T
diagnostic trouble code.

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) Check for A/T diagnostic trouble code.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is A/T DTCs "27" or "28" set?

YES <DTC 27 set> : Refer to

P.23A-121

, DTC 27:

Transmission Range Switch System (Open Circuit).

YES <DTC 28 set> : Refer to

P.23A-166

, DTC 28:

Transmission Range Switch System (Short Circuit).

NO : Go to Step 2.

AC305412

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTOMATIC TRANSAXLE DIAGNOSIS

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STEP 2. Check the transaxle control cable assembly.

Move the selector lever to each position. The manual control
lever position of the transmission range switch should match
the transmission range.
Q: Is the manual control lever position correct?

YES : Go to Step 3.
NO : Repair the transaxle control cable. Refer to

P.23A-383

, Transmission Range Switch and Control

Cable Adjustment. Retest the system to verify the
repair.

STEP 3. Check the engine.

Refer to GROUP 13A <2.4L Engine>, Diagnosis

− Trouble

Symptom Chart

− Starting

P.13A-38

Refer to GROUP 13B <3.8L Engine>, Diagnosis

− Trouble

Symptom Chart

− Starting

P.13B-37

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 starter.

(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 check for a binding oil pump. If
either of these components are damaged the transaxle 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. Refer to GROUP 23B,

Transaxle

P.23B-10

AC304078

<F4A4B>

AC210182AC

<F4A5A>

AC001857

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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, Transaxle

P.23B-10

. Confirm that the malfunc-

tion 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" 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 condition:)

• 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:

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

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

AC001858

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STEP 1. Using scan tool MB991958, check actuator test
item 02: Underdrive Solenoid Valve.

CAUTION

• 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-79

. Then

confirm that the symptom is eliminated.

STEP 2. Check the hydraulic pressure.

Shift the selector lever to the sport mode 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-29

, Hydraulic Pressure Test.

Q: Is the hydraulic pressure within the standard value?

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

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

P.23A-392

<F4A4B> or

P.23A-400

<F4A5A>, Transaxle

Assembly and GROUP 23B, Transaxle

P.23B-10

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