Infiniti FX35, FX50 (S51). Manual - part 700

P0461 FUEL LEVEL SENSOR

EC-341

< DTC/CIRCUIT DIAGNOSIS >

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P0461 FUEL LEVEL SENSOR

Description

INFOID:0000000005236920

The fuel level sensor is mounted in the fuel level sensor unit.
The sensor detects a fuel level in the fuel tank and transmits a signal to the “unified meter and A/C amp.”. The
“unified meter and A/C amp.” sends the fuel level sensor signal to the ECM through CAN communication line.
It consists of two parts, one is mechanical float and the other is variable resistor. Fuel level sensor output volt-
age changes depending on the movement of the fuel mechanical float.

DTC Logic

INFOID:0000000005236921

DTC DETECTION LOGIC

NOTE:
• If DTC P0461 is displayed with DTC UXXXX, first perform the trouble diagnosis for DTC UXXXX.
• If DTC P0461 is displayed with DTC P0607, first perform the trouble diagnosis for DTC P0607. Refer

to 

EC-358, "DTC Logic"

.

Driving long distances naturally affect fuel gauge level.
This diagnosis detects the fuel gauge malfunction of the gauge not moving even after a long distance has
been driven.

DTC CONFIRMATION PROCEDURE

1.

PERFORM COMPONENT FUNCTION CHECK

Perform component function check. Refer to 

EC-341, "Component Function Check"

.

Use component function check to check the overall function of the fuel level sensor. During this check, a 1st
trip DTC might not be confirmed.
Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Go to 

EC-342, "Diagnosis Procedure"

.

Component Function Check

INFOID:0000000005236922

1.

PRECONDITIONING

WARNING:

When performing the following procedure, always observe the handling of the fuel. Refer to 

FL-10,

"Removal and Installation"

.

TESTING CONDITION:
Before starting component function check, preparation of draining fuel and refilling fuel is required.

Will CONSULT-III be used?

YES

>> GO TO 2.

NO

>> GO TO 3.

2.

PERFORM COMPONENT FUNCTION CHECK

With CONSULT-III

NOTE:
Start from step 10, if it is possible to confirm that the fuel cannot be drained by 30   (7-7/8 US gal, 6-5/
8 Imp gal) in advance.
1.

Prepare a fuel container and a spare hose.

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0461

Fuel level sensor circuit 
range/performance

The output signal of the fuel level sensor does 
not change within the specified range even 
though the vehicle has been driven a long dis-
tance.

• Harness or connectors

(The CAN communication line is open or 
shorted)

• Harness or connectors

(The sensor circuit is open or shorted)

• Unified meter and A/C amp.
• Fuel level sensor

EC-342

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

P0461 FUEL LEVEL SENSOR

2.

Release fuel pressure from fuel line, refer to 

EC-566, "Inspection"

.

3.

Remove the fuel feed hose on the fuel level sensor unit.

4.

Connect a spare fuel hose where the fuel feed hose was removed.

5.

Turn ignition switch OFF and wait at least 10 seconds then turn ON.

6.

Select “FUEL LEVEL SE” in “DATA MONITOR” mode with CONSULT-III.

7.

Check “FUEL LEVEL SE” output voltage and note it.

8.

Select “FUEL PUMP RELAY” in “ACTIVE TEST” mode with CONSULT-III.

9.

Touch “ON” and drain fuel approximately 30   (7-7/8 US gal, 6-5/8 Imp gal) and stop it.

10. Check “FUEL LEVEL SE” output voltage and note it.
11. Fill fuel into the fuel tank for 30   (7-7/8 US gal, 6-5/8 Imp gal).
12. Check “FUEL LEVEL SE” output voltage and note it.
13. Confirm whether the voltage changes more than 0.03 V during step 7 to 10 and 10 to 12.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Go to 

EC-342, "Diagnosis Procedure"

.

3.

PERFORM COMPONENT FUNCTION CHECK

Without CONSULT-III

NOTE:
Start from step 8, if it is possible to confirm that the fuel cannot be drained by 30   (7-7/8 US gal, 6-5/8
Imp gal) in advance.
1.

Prepare a fuel container and a spare hose.

2.

Release fuel pressure from fuel line. Refer to 

EC-566, "Inspection"

.

3.

Remove the fuel feed hose on the fuel level sensor unit.

4.

Connect a spare fuel hose where the fuel feed hose was removed.

5.

Turn ignition switch ON.

6.

Drain fuel by 30   (7-7/8 US gal, 6-5/8 Imp gal) from the fuel tank using proper equipment.

7.

Confirm that the fuel gauge indication varies.

8.

Fill fuel into the fuel tank for 30   (7-7/8 US gal, 6-5/8 Imp gal).

9.

Confirm that the fuel gauge indication varies.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Go to 

EC-342, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000005236923

1.

CHECK DTC WITH “UNIFIED METER AND A/C AMP.”

Refer to 

MWI-45, "CONSULT-III Function (METER/M&A)"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Go to 

MWI-61, "Diagnosis Procedure"

.

2.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-36, "Intermittent Incident"

.

>> INSPECTION END

P0462, P0463 FUEL LEVEL SENSOR

EC-343

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

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EC

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P0462, P0463 FUEL LEVEL SENSOR

Description

INFOID:0000000005236924

The fuel level sensor is mounted in the fuel level sensor unit.
The sensor detects a fuel level in the fuel tank and transmits a signal to the “unified meter and A/C amp.”. The
“unified meter and A/C amp.” sends the fuel level sensor signal to the ECM through CAN communication line.
It consists of two parts, one is mechanical float and the other is variable resistor. Fuel level sensor output volt-
age changes depending on the movement of the fuel mechanical float.

DTC Logic

INFOID:0000000005236925

DTC DETECTION LOGIC

NOTE:
• If DTC P0462 or P0463 is displayed with DTC UXXXX, first perform the trouble diagnosis for DTC

UXXXX.

• If DTC P0462 or P0463 is displayed with DTC P0607, first perform the trouble diagnosis for DTC

P0607.Refer to 

EC-358, "DTC Logic"

.

This diagnosis indicates the former, to detect open or short circuit malfunction.

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.

TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 11 V at ignition
switch ON.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Turn ignition switch ON and wait at least 5 seconds.

2.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-343, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000005236926

1.

CHECK DTC WITH “UNIFIED METER AND A/C AMP.”

Refer to 

MWI-45, "CONSULT-III Function (METER/M&A)"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Go to 

MWI-61, "Diagnosis Procedure"

.

2.

CHECK INTERMITTENT INCIDENT

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0462

Fuel level sensor circuit 
low input

An excessively low voltage from the sensor is 
sent to ECM.

• Harness or connectors

(The CAN communication line is open or 
shorted)

• Harness or connectors

(The sensor circuit is open or shorted)

• Unified meter and A/C amp.
• Fuel level sensor

P0463

Fuel level sensor circuit 
high input

An excessively high voltage from the sensor is 
sent to ECM.

EC-344

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

P0462, P0463 FUEL LEVEL SENSOR

Refer to 

GI-36, "Intermittent Incident"

.

>> INSPECTION END