P0181
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.
[Reference data]
DTC Logic
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.INSPECTION START
Is it necessary to erase permanent DTC?
YES - GO TO 7.
NO - GO TO 2.
2.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 3.
3.PERFORM DTC CONFIRMATION PROCEDURE-I
1. Turn ignition switch ON and wait at least 10 seconds.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES - Go to SEE Diagnosis Procedure.
NO - GO TO 4.
4.CHECK ENGINE COOLANT TEMPERATURE
1. Select "COOLAN TEMP/S" in "DATA MONITOR" with CONSULT-III.
2. Check "COOLAN TEMP/S" value.
"COOLAN TEMP/S" less than 60�C (140�F)?
YES - INSPECTION END
NO - GO TO 5.
5.PERFORM DTC CONFIRMATION PROCEDURE-II
1. Cool engine down until "COOLAN TEMP/S" is less than 60�C (140�F).
2. Wait at least 10 seconds.
3. Check 1st trip DTC.
Is 1st trip DTC detected?
YES - Go to SEE Diagnosis Procedure.
NO - GO TO 6.
6.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.
7.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.
TEST CONDITION:
- Before performing the following procedure, do not add fuel.
- Before performing the following procedure, check that fuel level is between 1/4 and 4/4.
- Before performing the following procedure, confirm that battery voltage is 11 V or more at idle.
- GO TO 8.
8.PERFORM DTC CONFIRMATION PROCEDURE B
1. Start engine and let it idle for 60 minutes.
2. Move the vehicle to a cool place.
NOTE:
Cool the vehicle in an environment of ambient air temperature between -10�C (14�F) and 35�C (95�F).
3. Turn ignition switch OFF and soak the vehicle for 12 hours.
CAUTION:
Never turn ignition switch ON during soaking.
NOTE:
The vehicle must be cooled with the food open.
4. Start engine and let it idle for 5 minutes or more.
CAUTION:
Never turn ignition switch OFF during idling.
5. Check 1st trip DTC.
Is 1st trip DTC detected?
YES - Proceed to SEE Diagnosis Procedure.
NO - INSPECTION END
Component Function Check
1.CHECK FUEL TANK TEMPERATURE 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?
YES - GO TO 2.
NO - GO TO 7.
2.CHECK DTC WITH "UNIFIED METER AND A/C AMP."
.
Is the inspection result normal?
YES - GO TO 3.
NO - Go to Fuel Level Sensor Signal Circuit.
3.CHECK FUEL TANK TEMPERATURE 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 5.
NO - GO TO 4.
4.DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors M7, B1
- Harness for open or short between ECM and "fuel level sensor unit and fuel pump"
- Repair open circuit, short to ground or short to power in harness or connector.
5.CHECK FUEL TANK TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect "unified meter and A/C amp." harness connector.
3. Check the continuity between "fuel level sensor unit and fuel pump" harness connector and "unified meter and A/C amp." harness connector.
4. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES - GO TO 7.
NO - GO TO 6.
6.DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors M7, B1
- Harness for open or short between "fuel level sensor unit and fuel pump" and "unified meter and A/C amp."
- Repair open circuit, short to ground or short to power in harness or connector.
7.CHECK FUEL TANK TEMPERATURE SENSOR
SEE Component Inspection.
Is the inspection result normal?
YES - GO TO 8.
NO - Replace "fuel level sensor unit and fuel pump". Removal and Installation.
8.CHECK INTERMITTENT INCIDENT
Intermittent Incident.
- INSPECTION END
Component Inspection
1.CHECK FUEL TANK TEMPERATURE SENSOR
1. Turn ignition switch OFF.
2. Disconnect "fuel level sensor unit and fuel pump" harness connector.
3. Remove fuel level sensor unit.
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". Refer to
Removal and Installation.