Mitsubishi Galant. Manual — part 411

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-111

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 9.
NO : Go to Step 10.

STEP 9. Check connectors C-40 and C-42 at PCM for
damage.
Q: Are the connectors in good condition?

YES : Go to Step 4.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

.

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

ACX02131

NORMAL WAVEFORM

AB

(V)

5

0

AC004197

PCM

C-40

C-42

CONNECTORS: C-40, C-42

AE

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-112

STEP 10. Check connectors C-40 and C-42 at PCM and B-
37 at output shaft speed sensor for damage.
Q: Are the connectors in good condition?

YES : Go to Step 11.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

.

STEP 11. Check the continuity at output shaft speed
sensor connector B-37.
(1) Disconnect connector B-37 and measure at the harness

side.

(2) Check for the continuity between terminal 1 and ground.

•

Should be less than 2 ohm.

Q: Is the continuity normal?

YES : Go to Step 12.
NO : Repair it because of harness open circuit or damage

between output shaft speed sensor connector B-37
terminal 1 and PCM connector C-40 terminal 57.

AC004197

PCM

C-40

C-42

CONNECTORS: C-40, C-42

AE

AC001837AG

CONNECTOR: B-37

AC001837AG

CONNECTOR: B-37

ACX02136

HARNESS
CONNECTOR: B-37

AF

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-113

STEP 12. Check the sensor output voltage at output shaft
speed sensor connector B-37.
(1) Disconnect connector B-37 and measure at the harness

side.

(2) Turn the ignition switch to "ON" position.

(3) Measure the voltage between terminal 2 and ground.

•

Voltage should be between 4.8 and 5.2 volts.

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

Q: Is the voltage normal?

YES : Go to Step 13.
NO : Repair it because of harness open circuit between

output shaft speed sensor connector B-37 terminal 2
and PCM connector C-42 terminal 104.

STEP 13. Check the power supply voltage at output shaft
speed sensor connector B-37.
(1) Disconnect connector B-37 and measure at the harness

side.

(2) Turn the ignition switch to "ON" position.

(3) Measure the voltage between terminal 3 and ground.

•

Voltage should be battery positive voltage.

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

Q: Is the voltage normal?

YES : Go to Step 15.
NO : Go to Step 14.

AC001837AG

CONNECTOR: B-37

ACX02135

HARNESS
CONNECTOR: B-37

AF

AC001837AG

CONNECTOR: B-37

ACX02134

HARNESS
CONNECTOR: B-37

AF

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-114

STEP 14. Check connectors C-17 at intermediate
connector and C-77 at junction block for damage.
Q: Are the connectors in good condition?

YES : Repair it because of harness open circuit or short

circuit to ground between output shaft speed sensor
connector B-37 terminal 3 and junction block
connector C-77 terminal 12.

NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

.

STEP 15. Replace the output shaft speed sensor.
(1) Replace the output 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 "23" output?

YES : Go to Step 18.
NO : The inspection is complete.

AC004308AB

CONNECTOR: C-17

AC004307

CONNECTOR: C-77

JUNCTION BLOCK
(FRONT VIEW)

C-77

AC

AC001837AD

OUTPUT SHAFT
SPEED SENSOR