P0181
P0181 FTT SENSOR
Component 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.
[Reference data]
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 perform the following procedure before conducting the next test.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
- GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION A-I
1. Turn ignition switch ON and wait at least 10 seconds.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES - Proceed to SEE Diagnosis Procedure.
NO - GO TO 3.
3.CHECK ENGINE COOLANT TEMPERATURE
With CONSULT-III
1. Select "COOLANT TEMP/S" in "DATA MONITOR" with CONSULT-III.
2. Check "COOLANT TEMP/S" value.
With GST
Follow the procedure "With CONSULT-III" above.
"COOLANT TEMP/S" less than 60�C (140�F)?
YES - INSPECTION END
NO - GO TO 4.
4.PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION A-II
With CONSULT-III
1. Cool engine down until "COOLANT TEMP/S" is less than 60�C (140�F).
2. Wait at least 10 seconds.
3. Check 1st trip DTC.
With GST
Follow the procedure "With CONSULT-III" above.
Is 1st trip DTC detected?
YES - Proceed to SEE Diagnosis Procedure.
NO - GO TO 5.
5.PERFORM COMPONENT FUNCTION CHECK (FOR MALFUNCTION B)
Perform component function check. SEE Component Function Check.
NOTE:
Use the component function check to check the overall function of the FTT sensor circuit. During this check, a
1st trip DTC might not be confirmed.
Is the inspection result normal?
YES - INSPECTION END
NO - Proceed to SEE Diagnosis Procedure.
Component Function Check
1.CHECK FUEL TANK TEMPERATURE (FTT) SENSOR
1. Turn ignition switch OFF.
2. Disconnect fuel level sensor unit and fuel pump harness connector.
3. Remove fuel level sensor unit. Removal and Installation.
4. 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 - GO TO 2.
NO - Proceed to SEE Diagnosis Procedure.
2.CHECK INTERMITTENT INCIDENT
Check intermittent incident. Intermittent Incident.
Is the inspection result normal?
YES - INSPECTION END
NO - Proceed to SEE Diagnosis Procedure.
Diagnosis Procedure
1.INSPECTION START
Confirm the detected malfunction (A or B). SEE DTC Logic.
Which malfunction is detected?
A - GO TO 2.
B - GO TO 6.
2.CHECK FUEL TANK TEMPERATURE (FTT) SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect fuel level sensor unit and fuel pump harness connector.
3. Turn ignition switch ON.
4. 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 for open or short between ECM and fuel level sensor unit and fuel pump
- Loose or poor connection for each connector and harness
- Repair open circuit, short to ground or short to power in harness or connector.
4.CHECK FTT SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Check the continuity between fuel level sensor unit and fuel pump harness connector and ground.
3. 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 for open or short between fuel level sensor unit and fuel pump and ground
- Loose or poor connection for each connector and harness
- Repair open circuit, short to ground or short to power in harness or connector.
6.CHECK FTT SENSOR
Check FTT sensor. SEE Component Inspection.
Is the inspection result normal?
YES - GO TO 7.
NO - Replace fuel level sensor unit and fuel pump. Removal and Installation.
7.CHECK INTERMITTENT INCIDENT
Check intermittent incident. Intermittent Incident.
- INSPECTION END
Component Inspection
1.CHECK FUEL TANK TEMPERATURE (FTT) SENSOR
1. Turn ignition switch OFF.
2. Disconnect fuel level sensor unit and fuel pump harness connector.
3. Remove fuel level sensor unit. Removal and Installation.
4. 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. Removal and Installation.