Nissan Altima (L32) 2007-2012 Service Manual: 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>

*: These data are reference values and are measured between ECM terminal 95 (Fuel tank temperature sensor) and ground.

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

1. Turn ignition switch and wait at least 10 seconds.

2. Check 1st trip DTC.

Is 1st trip DTC detected? YES >> Go to EC-263, "Diagnosis Procedure".

NO >> GO TO 3.

3.CHECK ENGINE COOLANT TEMPERATURE

1. Select “COOLAN TEMP/S” in “DATA MONITOR” mode with CONSULT-III.

2. Check “COOLAN TEMP/S” value.

Follow the procedure “With CONSULT-III” above.

“COOLAN TEMP/S” less than 60°C (140°F)? YES >> INSPECTION END

NO >> GO TO 4.

4.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.

Follow the procedure “With CONSULT-III” above.

Is 1st trip DTC detected? YES >> Go to EC-263, "Diagnosis Procedure".

NO >> INSPECTION END

Diagnosis Procedure

1.CHECK GROUND CONNECTION

1. Turn ignition switch OFF.

2. Check ground connection E9. Refer to Ground Inspection in GI-45, "Circuit 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

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 connectors E29, B10

• 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

1. Turn ignition switch OFF.

2. Check the continuity between “fuel level sensor unit and fuel pump” harness connector and ECM harness connector.

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 connectors B1, M6

• Harness connectors E30, M1

• Harness for open or short between “fuel level sensor unit and fuel pump” and ECM

>> Repair open circuit or short to ground or short to power in harness or connector.

6.CHECK FUEL TANK TEMPERATURE SENSOR

Refer to EC-264, "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 GI-42, "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”.