Mitsubishi Galant. Manual — part 432

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-195

STEP 3. Using the oscilloscope, check the waveform at
PCM connectors C-40 and C-42 by backprobing.
(1) Do not disconnect connectors C-40 and C-42.

(2) Connect an oscilloscope probe to PCM connector C-40

terminal 57 and to PCM connector C-42 terminal 103 by
backprobing.

(3) Start the engine and run at constant speed of 50km/h

(31mph). (Gear range: 3rd gear)

(4) Check the waveform.

•

The waveform should show a pattern similar to the
illustration. The maximum value should be 4.8 volts and
more and the minimum value 0.8 volts and less. The
output waveform should not contain the noise.

(5) Turn the ignition switch to "LOCK" (OFF) position.

Q: Is the waveform normal?

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

AC004197

PCM

C-40

C-42

CONNECTORS: C-40, C-42

AE

AC001899

C-42 CONNECTOR HARNESS SIDE VIEW

C-40 CONNECTOR HARNESS SIDE VIEW

AE

OSCILLO-
SCOPE

PROBE

ACX02131AB

NORMAL WAVEFORM

(V)

5

0

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-196

STEP 4. Check connectors B-40 at input shaft speed
sensor and C-42 at PCM for damage.
Q: Are the connectors in good condition?

YES : Go to Step 5.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

.

STEP 5. Check harness for damage between input shaft
speed sensor connector B-40 terminal 2 and PCM
connector C-42 terminal 103.
Q: Is the harness wire in good condition?

YES : Go to Step 6.
NO : Repair it.

AC001835

CONNECTOR: B-40

AF

AC004197

PCM

AF

CONNECTOR: C-42

AC001835

CONNECTOR: B-40

AF

AC004197

PCM

AF

CONNECTOR: C-42

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-197

STEP 6. Replace the input shaft speed sensor.
(1) Replace the input shaft speed sensor. Refer to GROUP

23B, Transaxle

P.23B-10

.

(2) Carry out a test drive.
(3) Read in the A/T diagnostic trouble code.

Q: Is the A/T diagnostic trouble code output?

YES : Go to Step 7.
NO : The inspection is complete.

STEP 7. Replace the underdrive clutch retainer.
(1) Replace the underdrive clutch retainer. Refer to GROUP

23B, Underdrive Clutch and Input Shaft

P.23B-51

.

(2) Carry out a test drive.
(3) Read in the A/T diagnostic trouble code.

Q: Is the A/T diagnostic trouble code output?

YES : The A/T diagnostic trouble code may have set due to

external radio frequency (RFI), possibly caused by
cellular phone activity, after market components
installed on the vehicle, etc.

NO : The inspection is complete.

AC001835

INPUT SHAFT
SPEED SENSOR

AC

AC001836AB

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-198

STEP 8. Using the oscilloscope, check the waveform at
PCM connectors C-40 and C-42 by backprobing.
(1) Do not disconnect connectors C-40 and C-42.

(2) Connect an oscilloscope probe to PCM connector C-40

terminal 57 and to PCM connector C-42 terminal 104 by
backprobing.

(3) Start the engine and run at constant speed of 50km/h

(31mph). (Gear range: 3rd gear)

(4) Check the waveform.

•

The waveform should show a pattern similar to the
illustration. The maximum value should be 4.8 volts and
more and the minimum value 0.8 volts and less. The
output waveform should not contain the noise.

(5) Turn the ignition switch to "LOCK" (OFF) position.

Q: Is the waveform normal?

YES : Go to Step 13.
NO : Go to Step 9.

AC004197

PCM

C-40

C-42

CONNECTORS: C-40, C-42

AE

AC001900

C-42 CONNECTOR HARNESS SIDE VIEW

C-40 CONNECTOR HARNESS SIDE VIEW

AE

OSCILLO-
SCOPE

PROBE

ACX02131AB

NORMAL WAVEFORM

(V)

5

0