2005 MITSUBISHI 380 Workshop Manual

AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-38
STEP 2. Measure the sensor output voltage at the A/T
control solenoid valve assembly connector B-108 by
backprobing.
(1) Do not disconnect connector B-108.
(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 20C, voltage
should measure between 3.8 and 4.0 volts.
When transmission fluid temperature is 40C, voltage
should measure between 3.2 and 3.4 volts.
When transmission fluid temperature is 80C, 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. Measure the ground voltage at the A/T control
solenoid valve assembly connector B-108 by backprobing.
(1) Do not disconnect connector B-108.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 2 and ground by
backprobing.
The voltage should measure 0.5 volt or less.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage 0.5 volt or less?
YES : Go to Step 4.
NO : Go to Step 7.

AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-39
STEP 4. Check the sensor output voltage at A/T control
solenoid valve assembly connector B-108.
(1) Disconnect connector B-108 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 9.

AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-40
STEP 5. Check the transmission fluid temperature sensor
at A/T control solenoid valve assembly connector B-108.
(1) Disconnect connector B-108 and measure at the sensor
side.
(2) Measure the resistance between terminal 1 and 2.
When transmission fluid temperature is 0C (32F),
resistance should be between 16.7 and 20.5 k
.
When transmission fluid temperature is 20C (68F),
resistance should be between 7.3 and 8.9 k
.
When transmission fluid temperature is 40C (104F),
resistance should be between 3.4 and 4.2 k
.
When transmission fluid temperature is 60C (140F),
resistance should be between 1.9 and 2.2 k
.
When transmission fluid temperature is 80C (176F),
resistance should be between 1.0 and 1.2 k
.
When transmission fluid temperature is 100C (212F),
resistance should be between 0.57 and 0.69 k
.
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-13.

AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-41
STEP 6. Using diagnostic tool MB991958, check data list
item 7: Transmission Fluid Temperature Sensor.
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
(1) Connect diagnostic tool MB991958 to the data link
connector.
(2) Start the engine.
(3) Set diagnostic tool MB991958 to the data reading mode.
Item 7: Transmission Fluid Temperature Sensor.
When the engine is cool: Diagnostic tool display is
almost equal to the ambient temperature (atmo-
spheric temperature)
NOTE: Set diagnostic tool MB991958 to the Engine
MPI data list reading mode for item number 5, Intake
Air Temperature (IAT) Sensor and note the tempera-
ture 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 approximately the
same as the Transmission Fluid Temperature Sen-
sor.
When the engine is warm, at approximately running
temperature: 70
80C.
(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.00-14.
NO : Replace the A/T-ECU.
STEP 7. Check A/T control solenoid valve assembly
connector B-108 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 8.
NO : Repair or replace the damaged components. Refer to
GROUP 00E, Harness Connector Inspection
P.00E-2.