Code No.
P0713: Transmission Fluid
Temperature Sensor High <M/T>
OPERATION
A power voltage of 5 V is applied to the transmission fluid temperature
sensor output terminal from the engine-ECU connector terminal OTS.
The power voltage is earthed to the engine-ECU connector terminal OTSE
from the transmission fluid temperature sensor connector terminal.
FUNCTION
The transmission fluid temperature sensor converts the transmission fluid
temperature into a voltage signal, and inputs the voltage to the engine-ECU.
In response to the signal, the engine-ECU controls the fuel infection amount
and the fast idle speed when the engine is cold state.
The transmission fluid temperature sensor is a kind of resistor, which has
characteristics to reduce its resistance as the transmission fluid temperature
rises. Therefore, the sensor output voltage varies with the transmission fluid
temperature, and becomes lower as the transmission fluid temperature
rises.
TROUBLE JUDGEMENT
Check Conditions
Battery positive voltage is 8 - 16 V.
2 seconds later after the ignition switch has been in "ON" position or the
engine has started up.
Judgement Criterion
The transmission fluid temperature sensor output voltage is 4.95 V or more.
FAIL-SAFE AND BACKUP FUNCTION
The transmission fluid temperature is controlled to be 140°C (Start-up of -
25°C).
The EGR control is stopped (fully closed).
The throttle valve is opened (Electrical discontinuity).
The DPF regeneration is prohibited.
The AS&G control is prohibited.
PROBABLE CAUSES
Failed transmission fluid temperature sensor
Open circuit or harness damage in transmission fluid temperature sensor
circuit or loose connector contact
Failed engine-ECU
DIAGNOSIS PROCEDURE
STEP 1. Perform resistance
measurement at
transmission fluid
temperature sensor
connector.
Transmission fluid temperature sensor
connector check.
Disconnect connector, and measure at
sensor side.
Resistance between terminals.
OK:
Transmission fluid temperature at -
20°C: 14 - 17 kΩ
(Transmission fluid temperature at
0°C: 5.1 - 6.5 kΩ)
Transmission fluid temperature at
20°C: 2.1 - 2.7 kΩ
(Transmission fluid temperature at
40°C: 0.9 - 1.3 kΩ)
(Transmission fluid temperature at
60°C: 0.48 - 0.68 kΩ)
(Transmission fluid temperature at
80°C: 0.26 - 0.36 kΩ)
Q. Is the check result normal?
Go to Step 2.
Repair or replace the connector,
or replace the transmission fluid temperature
sensor.
STEP 2. Perform voltage
measurement at
transmission fluid
temperature sensor
connector.
Disconnect connector, and measure at
harness side.
Ignition switch: "ON"
Voltage between terminal engine-ECU
OTS line and body earth.
OK: 4.5 - 4.9 V
Q. Is the check result normal?
Go to Step 5.
Go to Step 3.
STEP 3. Check harness
between transmission fluid
temperature sensor
connector terminal and
engine-ECU connector
terminal OTS.
Check output line for open circuit and
damage.
Q. Is the check result normal?
Go to Step 4.
Repair or replace the connector,
or repair the damaged harness wire.
STEP 4. M.U.T.-III diagnosis
code
Reconfirmation of diagnosis code.
Q. Is the diagnosis code set?
Replace the engine-ECU.
Intermittent malfunction (Refer to
GROUP 00 - How to Use
Troubleshooting/Inspection Service Points -
How to Cope with Intermittent Malfunctions
).
STEP 5. Perform resistance
measurement at
transmission fluid
temperature sensor
connector.
Disconnect connector, and measure at
harness side.
Resistance between terminal engine-
ECU OTSE line and body earth.
OK: Continuity (2 Ω or less)
Q. Is the check result normal?
Go to Step 4.
Go to Step 6.
STEP 6. Check harness
between transmission fluid
temperature sensor
connector terminal and
engine-ECU connector
terminal OTSE.
Check earthing line for open circuit and
damage.
Q. Is the check result normal?
Go to Step 4.
Repair or replace the connector,
or repair the damaged harness wire.
