Mitsubishi Eclipse. Manual - part 770

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-89

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 data reading mode for item 15: 

Transmission Fluid Temperature Sensor.

• When the engine is cool: Almost equal to the ambient 

temperature (atmospheric temperature)
NOTE: Set scan tool MB991958 to data reading mode 
for item number 13, Intake Air Temperature (IAT) Sensor 
and note the temperature measurement. When the 
engine is cool, the temperature should be almost equal 
to the ambient temperature (atmospheric temperature), 
and the IAT sensor measurement should be approxi-
mately 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.

AC303127

AB

MB991911

16-PIN

MB991827

MB991824 

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-90

STEP 2. Measure the sensor output voltage at the A/T 
control solenoid valve assembly connector B-40 by 
backprobing.
(1) Do not disconnect connector B-40.
(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 B-40 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

.

ACX02479

CONNECTOR: B-40

AK

B-40

5

2

1

7

3

8

4

9

6

10

AC200996AI

B-40 HARNESS
CONNECTOR: 
HARNESS SIDE

ACX02479

CONNECTOR: B-40

AK

B-40

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-91

STEP 4. Check the sensor output voltage at A/T control 
solenoid valve assembly connector B-40.
(1) Disconnect connector B-40 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.

ACX02479

CONNECTOR: B-40

AK

B-40

ACX02104

B-40 HARNESS
CONNECTOR:
COMPONENT SIDE

AM

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-92

STEP 5. Check the transmission fluid temperature sensor 
at A/T control solenoid valve assembly connector B-40.
(1) Disconnect connector B-40 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, Transaxle 

P.23B-10

.

ACX02479

CONNECTOR: B-40

AK

B-40

ACX02103

B-40 HARNESS 
CONNECTOR: 
TRANSMISSION
FLUID TEMPERATURE
SENSOR SIDE

AQ