Mitsubishi Montero (2004+). Manual — part 872

AUTOMATIC TRANSMISSION DIAGNOSIS

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AUTOMATIC TRANSMISSION

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STEP 1. Using scan tool MB991958, check data list item 15:
Transmission Fluid Temperature Sensor.

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) Start the engine.
(3) Set scan tool MB991958 to the data reading mode.

• Item 15: Transmission Fluid Temperature Sensor.

• When the engine is cool: Almost equal to the ambi-

ent temperature (atmospheric temperature)
NOTE: Set scan tool MB991958 to the data reading
mode for item number 13, Intake Air Temperature
(IAT) Sensor and note the temperature measure-
ment. When the engine is cool, the temperature
should be almost equal to the ambient temperature
(atmospheric temperature), and the IAT sensor mea-
surement should be approximately the same as the
Transmission Fluid Temperature Sensor.

• When the engine is warm: 70 to 80°C (158 to 176°F)

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?

YES : It can be assumed that this malfunction is intermittent.

Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

− How to

Cope with Intermittent Malfunction

P.00-6

.

NO : Go to Step 2.

AC307591 AC

MB991911

MB991824

MB991827

AC307591

DATA LINK

CONNECTOR

AUTOMATIC TRANSMISSION DIAGNOSIS

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AUTOMATIC TRANSMISSION

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STEP 2. Measure the sensor output voltage at the A/T
control solenoid valve assembly connector C-03 by
backprobing.
(1) Do not disconnect connector C-03.
(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal 1 and ground by

backprobing.

• When transmission fluid temperature is 20°C (68°F),

voltage should measure between 3.8 and 4.0 volts.

• When transmission fluid temperature is 40°C (104°F),

voltage should measure between 3.2 and 3.4 volts.

• When transmission fluid temperature is 80°C (176°F),

voltage should measure between 1.7 and 1.9 volts.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage within the specified range?

YES : Go to Step 6.
NO : Go to Step 3.

STEP 3. Check A/T control solenoid valve assembly
connector C-03 for loose, corroded or damaged terminals,
or terminals pushed back in the connector.
Q: Are the connector and terminals in good condition?

YES : Go to Step 4.
NO : Repair or replace the damaged components. Refer to

GROUP 00E, Harness Connector Inspection

P.00E-2

.

AC204395

CONNECTOR : C-03

AE

C-03 (B)

6

10

4

9

5

3

8

2

7

1

AC204918 AI

C-03 HARNESS CONNECTOR :
HARNESS SIDE

6

9

5

10

8

3

7

2

1

4

AC204395

CONNECTOR : C-03

AE

C-03 (B)

6

10

4

9

5

3

8

2

7

1

AUTOMATIC TRANSMISSION DIAGNOSIS

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STEP 4. Check the sensor output voltage at A/T control
solenoid valve assembly connector C-03.
(1) Disconnect connector C-03 and measure at the harness

side.

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

(3) Measure the voltage between terminal 1 and ground.

• The voltage should measure between 4.5 and 4.9 volts.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.5 and 4.9 volts?

YES : Go to Step 5.
NO : Go to Step 7.

AC204395

CONNECTOR : C-03

AE

C-03 (B)

6

10

4

9

5

3

8

2

7

1

AC204918 AJ

C-03 HARNESS CONNECTOR :
COMPONENT SIDE

1

8

2

7

9

4

10

5

6

3

AUTOMATIC TRANSMISSION DIAGNOSIS

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STEP 5. Check the transmission fluid temperature sensor
at A/T control solenoid valve assembly connector C-03.
(1) Disconnect connector C-03 and measure at the sensor

side.

(2) Measure the resistance between terminal 1 and 2.

• When transmission fluid temperature is 0°C (32°F),

resistance should be between 16.7 and 20.5 k

Ω.

• When transmission fluid temperature is 20°C (68°F),

resistance should be between 7.3 and 8.9 k

Ω.

• When transmission fluid temperature is 40°C (104°F),

resistance should be between 3.4 and 4.2 k

Ω.

• When transmission fluid temperature is 60°C (140°F),

resistance should be between 1.9 and 2.2 k

Ω.

• When transmission fluid temperature is 80°C (176°F),

resistance should be between 1.0 and 1.2 k

Ω.

• When transmission fluid temperature is 100°C (212°F),

resistance should be between 0.57 and 0.69 k

Ω.

Q: Is the measured resistance within the specified range?

YES : Go to Step 6.
NO : Replace the transmission fluid temperature sensor.

Refer to GROUP 23B, Transmission

P.23B-14

.

AC204395

CONNECTOR : C-03

AE

C-03 (B)

6

10

4

9

5

3

8

2

7

1

AC204918

C-03 HARNESS CONNECTOR :
SOLENOID VALVE SIDE

CS

6

10

4

9

5

3

8

2

7

1