What is FTT? Or code P0181 malfunction?

P0181 FTT SENSOR

Description

The fuel tank temperature sensor is used to detect the fuel temperature inside the fuel tank. The sensor modifies a voltage signal from the ECM. The modified signal returns to the ECM as the fuel temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.

CAUTION: Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.

DTC Logic

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE
1. PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test.
>> GO TO 2.
2. PERFORM DTC CONFIRMATION PROCEDURE-I

Turn ignition switch and wait at least 10 seconds.
Check 1st trip DTC. Is 1st trip DTC detected?

YES >> Go to "Diagnosis Procedure".
NO >> GO TO 3.
3. CHECK ENGINE COOLANT TEMPERATURE
With CONSULT-III

Select "COOLAN TEMP/S" in "DATA MONITOR" mode with CONSULT-III.
Check "COOLAN TEMP/S" indication. With GST

Follow the procedure "With CONSULT-III" above.
Is "COOLAN TEMP/S" indication less than 60°C (140°F)?
YES >> INSPECTION END
NO >> GO TO 4.
4. PERFORM DTC CONFIRMATION PROCEDURE-II
With CONSULT-III

Cool engine down until "COOLAN TEMP/S" indication is less than 60°C (140°F).
Wait at least 10 seconds.
Check 1st trip DTC. With GST

Follow the procedure "With CONSULT-III" above.
Is 1st trip DTC detected?
YES >> Go to "Diagnosis Procedure".
NO >> INSPECTION END

Wiring Diagram

Diagnosis Procedure
1. CHECK GROUND CONNECTION

Turn ignition switch OFF.
Check ground connections E15, E24. Refer to See: Powertrain Management Computers and Control Systems Testing and Inspection Component Tests and General Diagnostics Power Supply And Ground Circuit Ground Inspection. Is the inspection result normal?

YES >> GO TO 2.
NO >> Repair or replace ground connection.
2. CHECK FUEL TANK TEMPERATURE SENSOR POWER SUPPLY CIRCUIT

Turn ignition switch OFF.
Disconnect "fuel level sensor unit and fuel pump" harness connector.
Turn ignition switch ON.

Check the voltage between "fuel level sensor unit and fuel pump" harness connector and ground.

Is the inspection result normal?
YES >> GO TO 4.
NO >> GO TO 3.
3. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors B102, M13
Harness connectors M69, E7
Harness connectors E8, F8
Harness for open or short between ECM and "fuel level sensor unit and fuel pump" >> Repair open circuit or short to ground or short to power in harness or connector.

4. CHECK FUEL TANK TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

Turn ignition switch OFF.
Disconnect combination meter harness connector.
Check the continuity between "fuel level sensor unit and fuel pump" harness connector and combination meter harness connector.

Also check harness for short to ground and short to power. Is the inspection result normal?

YES >> GO TO 6.
NO >> GO TO 5.
5. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors B102, M13
Harness for open or short between "fuel level sensor unit and fuel pump" and combination meter >> Repair open circuit or short to ground or short to power in harness or connector.

6. CHECK FUEL TANK TEMPERATURE SENSOR
Refer to "Component Inspection".
Is the inspection result normal?
YES >> GO TO 7.
NO >> Replace "fuel level sensor unit and fuel pump".
7. CHECK INTERMITTENT INCIDENT
Refer to See: Powertrain Management Computers and Control Systems Testing and Inspection Initial Inspection and Diagnostic Overview Trouble Diagnosis For Intermittent Incident Diagnosis Procedure.
>> INSPECTION END

Component Inspection
1. CHECK FUEL TANK TEMPERATURE SENSOR

Turn ignition switch OFF.
Disconnect "fuel level sensor unit and fuel pump" harness connector.
Remove fuel level sensor unit.

Check resistance between "fuel level sensor unit and fuel pump" terminals by heating with hot water as shown in the figure.

Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace "fuel level sensor unit and fuel pump".