Infiniti QX56 (Z62). Manual - part 593

EC-350

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P0456 EVAP CONTROL SYSTEM

NO

>> Replace EVAP control system pressure sensor. Refer to 

EC-335, "Component Inspection (EVAP

Control System Pressure Sensor)"

.

16.

CHECK EVAP PURGE LINE

Check EVAP purge line (pipe, rubber tube, fuel tank and EVAP canister) for cracks or improper connection.
Refer to 

FL-10, "Hydraulic Layout"

.

Is the inspection result normal?

YES

>> GO TO 17.

NO

>> Repair or reconnect the hose.

17.

CLEAN EVAP PURGE LINE

Clean EVAP purge line (pipe and rubber tube) using air blower.

>> GO TO 18.

18.

CHECK EVAP/ORVR LINE

Check EVAP/ORVR line between EVAP canister and fuel tank for clogging, kink, looseness and improper con-
nection. For location, refer to 

FL-10, "Hydraulic Layout"

.

Is the inspection result normal?

YES

>> GO TO 19.

NO

>> Repair or replace hoses and tubes.

19.

CHECK RECIRCULATION LINE

Check recirculation line between fuel filler tube and fuel tank for clogging, kink, cracks, looseness and
improper connection.

Is the inspection result normal?

YES

>> GO TO 20.

NO

>> Repair or replace hose, tube or fuel filler tube. Refer to 

FL-8, "Exploded View"

.

20.

CHECK REFUELING EVAP VAPOR CUT VALVE

Refer to 

EC-518, "Component Inspection (EVAP Vapor Cut Valve)"

.

Is the inspection result normal?

YES

>> GO TO 21.

NO

>> Replace refueling EVAP vapor cut valve with fuel tank. Refer to 

FL-10, "Exploded View"

.

21.

CHECK FUEL LEVEL SENSOR

Refer to 

MWI-70, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 22.

NO

>> Replace fuel level sensor unit. Refer to 

FL-5, "Removal and Installation"

.

22.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-40, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection (Fuel Filler Cap)

INFOID:0000000006288327

1.

CHECK FUEL FILLER CAP

1.

Turn ignition switch OFF.

2.

Remove fuel filler cap.

P0456 EVAP CONTROL SYSTEM

EC-351

< DTC/CIRCUIT DIAGNOSIS >

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3.

Wipe clean valve housing.

4.

Install fuel filler cap adapter (commercial service tool) to fuel
filler cap.

5.

Check valve opening pressure and vacuum.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 2.

2.

REPLACE FUEL FILLER CAP

Replace fuel filler cap.

CAUTION:

Use only a genuine fuel filler cap as a replacement. If an incorrect fuel filler cap is used, the MIL may
illuminate.

>> INSPECTION END

SEF445Y

Pressure:

15.3 - 20.0 kPa (0.156 - 0.204 kg/cm

2

, 2.22 - 

2.90 psi)

Vacuum:

−

6.0 to 

−

3.3 kPa (

−

0.061 to 

−

0.034 kg/cm

2

, 

−

0.87 to 

−

0.48 psi)

SEF943S

EC-352

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P0460 FUEL LEVEL SENSOR

P0460 FUEL LEVEL SENSOR

DTC Logic

INFOID:0000000006288328

DTC DETECTION LOGIC

NOTE:
• If DTC P0460 is displayed with DTC UXXXX, first perform the trouble diagnosis for DTC UXXXX.
• If DTC P0460 is displayed with DTC P0607, first perform the trouble diagnosis for DTC P0607. Refer

to 

EC-378, "DTC Logic"

.

When the vehicle is parked, the fuel level in the fuel tank is naturally stable. It means that output signal of the
fuel level sensor does not change. If ECM senses sloshing signal from the sensor, fuel level sensor malfunc-
tion is detected.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

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

1.

Start engine and wait maximum of 2 consecutive minutes.

2.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Proceed to 

EC-352, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000006288329

1.

CHECK DTC WITH “COMBINATION METER”

Refer to 

MWI-30, "CONSULT-III Function"

.

Is any DTC detected?

YES

>> Perform trouble diagnosis of detected DTC.

NO

>> GO TO 2.

2.

CHECK FUEL LEVEL SENSOR SIGNAL CIRCUIT

Check fuel level sensor signal circuit. Refer to 

MWI-69, "Component Function Check"

.

Is the inspection result normal?

YES

>> Check intermittent incident. Refer to 

GI-40, "Intermittent Incident"

.

NO

>> Perform trouble diagnosis of fuel level sensor signal circuit. Refer to 

MWI-69,

"Diagnosis Procedure"

.

DTC No.

Trouble diagnosis name

(Trouble diagnosis content)

DTC detecting condition

Possible cause

P0460

FUEL LEV SEN SLOSH
(Fuel level sensor circuit 
noise)

Even though the vehicle is parked, a 
signal being varied is sent from the 
fuel level sensor to ECM.

• Harness or connectors

(The CAN communication line is open or shorted)

• Harness or connectors

(The sensor circuit is open or shorted)

• Combination meter
• Fuel level sensor

P0461 FUEL LEVEL SENSOR

EC-353

< DTC/CIRCUIT DIAGNOSIS >

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P0461 FUEL LEVEL SENSOR

DTC Logic

INFOID:0000000006288330

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-378, "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-353, "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

>> Proceed to 

EC-354, "Diagnosis Procedure"

.

Component Function Check

INFOID:0000000006288331

1.

PRECONDITIONING

WARNING:

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

FL-2,

"General Precautions"

.

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

>> GO TO 2.

2.

PERFORM COMPONENT FUNCTION CHECK

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-153, "Work Procedure"

.

3.

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

FL-5, "Removal and Installation"

.

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?

DTC No.

Trouble diagnosis name

(Trouble diagnosis content)

DTC detecting condition

Possible cause

P0461

FUEL LEVEL SENSOR
(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 distance.

• Harness or connectors

(The CAN communication line is open or short-
ed)

• Harness or connectors

(The sensor circuit is open or shorted)

• Combination meter
• Fuel level sensor