Nissan Sentra B18 (2020-2025) Service Manual: P0456 Evap Control System

Nissan Sentra B18 (2020-2025) Service Manual / Engine / Work Procedure (After Replacing Electric Throttle Control Actuator) / Dtc/circuit Diagnosis / P0456 Evap Control System

Dtc Description

DTC Description

This diagnosis detects leaks in the EVAP line between fuel tank and EVAP canister purge volume control solenoid valve, using the negative pressure caused by decrease of fuel temperature in the fuel tank after turning ignition switch OFF.

If ECM judges there are no leaks, the diagnosis will be OK.

DTC DETECTION LOGIC

DTC	CONSULT screen terms (Trouble diagnosis content)	DTC detection condition
P0456	EVAP VERY SML LEAK [Evaporative emission system leak detected (very small leak)]	Diagnosis condition	—
		Signal (terminal)	—
		Threshold	EVAP system has a leak EVAP system does not operate properly
		Diagnosis delay time	—

CAUTION:

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

If the fuel filler cap is not tightened properly, the MIL may illuminate.

Use only a genuine NISSAN rubber tube as a replacement.

POSSIBLE CAUSE

Incorrect fuel tank vacuum relief valve
Incorrect fuel filler cap used
Fuel filler cap remains open or does not close.
Foreign matter caught in fuel filler cap.
Leak is in line between intake manifold and EVAP canister purge volume control solenoid valve.
Foreign matter caught in EVAP canister vent control valve.
EVAP canister or fuel tank leaks
EVAP purge line (pipe and rubber tube) leaks
EVAP purge line rubber tube bent
Loose or disconnected rubber tube
EVAP canister vent control valve and the circuit
EVAP canister purge volume control solenoid valve and the circuit
Fuel tank temperature sensor
O-ring of EVAP canister vent control valve is missing or damaged
EVAP canister is saturated with water
EVAP control system pressure sensor
Refueling EVAP vapor cut valve
ORVR system leaks
Fuel level sensor and the circuit
Foreign matter caught in EVAP canister purge volume control solenoid valve

FAIL-SAFE

Not applicable

Confirmation Procedure

Confirmation Procedure

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.

Do you have CONSULT?
YES >>
GO TO 2.
NO >>
GO TO 4.
PERFORM DTC CONFIRMATION PROCEDURE-1

With CONSULT
1. Turn ignition switch ON and select “EVAP DIAG READY” in “DATA MONITOR” mode of “ENGINE” using CONSULT.
2. Start the engine and wait at idle until “OFF” of “EVAP DIAG READY” changes to “ON”.
  Note:
  It will take at most 2 hours until “OFF” of “EVAP DIAG READY” changes to “ON”.
3. Turn ignition switch OFF and wait at least 90 minutes.
  Note:
  Never turn ignition switch ON during 90 minutes.
4. Turn ignition switch ON and select “EVAP LEAK DIAG” in “DATA MONITOR” mode of “ENGINE” using CONSULT.
5. Check that “EVAP LEAK DIAG” indication.
Which is displayed on CONSULT?
CMPLT>>
GO TO 3.
YET>>
Perform DTC CONFIRMATION PROCEDURE again. GO TO 1.
PERFORM DTC CONFIRMATION PROCEDURE-2

Check 1st trip DTC.

Is 1st trip DTC detected?
YES >>
Proceed to DTC Diagnosis Procedure.
NO-1 >>
To check malfunction symptom before repair: Refer to Intermittent Incident.
NO-2 >>
Confirmation after repair: INSPECTION END
PERFORM DTC CONFIRMATION PROCEDURE

With GST
1. Start the engine and wait engine idle for at least 2 hours.
2. Turn ignition switch OFF and wait at least 90 minutes.
  Note:
  Never turn ignition switch ON during 90 minutes.
3. Turn ignition switch ON.
4. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >>
Proceed to DTC Diagnosis Procedure.
NO-1 >>
To check malfunction symptom before repair: Refer to Intermittent Incident.
NO-2 >>
Confirmation after repair: INSPECTION END

Dtc Diagnosis Procedure

DTC Diagnosis Procedure

CHECK FUEL FILLER CAP DESIGN
1. Turn ignition switch OFF.
2. Check for genuine NISSAN fuel filler cap design.
Is the inspection result normal?
YES >>
GO TO 2.
NO >>
Replace with genuine NISSAN fuel filler cap.
CHECK FUEL FILLER CAP INSTALLATION

Check that the cap is tightened properly by rotating the cap clockwise.

Is the inspection result normal?
YES >>
GO TO 3.
NO >>
Open fuel filler cap, then clean cap and fuel filler neck threads using air blower. Then retighten until reteaching sound is heard.
CHECK FUEL FILLER CAP FUNCTION

Check for air releasing sound while opening the fuel filler cap.

Is the inspection result normal?
YES >>
GO TO 5.
NO >>
GO TO 4.
CHECK FUEL TANK VACUUM RELIEF VALVE

Refer to Component Inspection.

Is the inspection result normal?
YES >>
GO TO 5.
NO >>
Replace fuel filler cap with a genuine one.
CHECK FOR EVAP LEAK

Refer to EVAP CANISTER : Periodic Maintenance.

Is there any leak in EVAP line?
YES >>
Repair or replace.
NO >>
GO TO 6.
CHECK EVAP CANISTER VENT CONTROL VALVE

Check the following.
- EVAP canister vent control valve is installed properly.
  
  Refer to Exploded View.
- EVAP canister vent control valve.
  
  Refer to Component Inspection.
Is the inspection result normal?
YES >>
GO TO 7.
NO >>
Repair or replace EVAP canister vent control valve and O-ring. Refer to Exploded View.
CHECK IF EVAP CANISTER SATURATED WITH WATER
1. Remove EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor attached.
2. Check if water will drain from the EVAP canister.
Does water drain from EVAP canister?
YES >>
GO TO 8.
NO-1 >>
With CONSULT: GO TO 10.
NO-2 >>
Without CONSULT: GO TO 11.
CHECK EVAP CANISTER

Weigh the EVAP canister assembly with the EVAP canister vent control valve and EVAP control system pressure sensor attached. Refer to Removal and Installation.

The weight should be less than 2.1 kg (4.6 lb).

Is the inspection result normal?
YES-1 >>
With CONSULT: GO TO 10.
YES-2 >>
Without CONSULT: GO TO 11.
NO >>
GO TO 9.
DETECT MALFUNCTIONING PART

Check the following.
- EVAP canister for damage
- EVAP hose between EVAP canister and Nissan Sentra vehicle frame for clogging or poor connection
>>
Repair hose or replace EVAP canister. Refer to Removal and Installation.

CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE OPERATION

With CONSULT

Disconnect vacuum hose to EVAP canister purge volume control solenoid valve at EVAP service port. Refer to Exploded View.
Start the engine and let it idle.
Select “PURG VOL CONT/V” in “ACTIVE TEST” mode of “ENGINE” using CONSULT.
Touch “Qu” on CONSULT screen to increase “PURG VOL CONT/V” opening to 100%.

Check vacuum hose for vacuum.

Vacuum should exist.

Is the inspection result normal?

YES >>

GO TO 13.

NO >>

GO TO 12.

CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE OPERATION

Without CONSULT

Start the engine and warm it up to normal operating temperature.
Stop the engine.
Disconnect vacuum hose to EVAP canister purge volume control solenoid valve at EVAP service port. Refer to Exploded View.
Start the engine and let it idle for at least 80 seconds.

Check vacuum hose for vacuum when revving engine up to 2,000 rpm.

Vacuum should exist.

Is the inspection result normal?

YES >>

GO TO 13.

NO >>

GO TO 12.

CHECK VACUUM HOSE

Check vacuum hoses for clogging or disconnection.

Is the inspection result normal?
YES >>
GO TO 13.
NO >>
Repair or reconnect the hose.
CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE

Check the EVAP canister purge volume control solenoid valve. Refer to Component Inspection.

Is the inspection result normal?
YES >>
GO TO 14.
NO >>
Replace EVAP canister purge volume control solenoid valve. Refer to Exploded View.
CHECK FUEL TANK TEMPERATURE SENSOR

Check the fuel tank temperature sensor. Refer to Component Inspection.

Is the inspection result normal?
YES >>
GO TO 15.
NO >>
Replace fuel level sensor unit, fuel filter and fuel pump assembly (with fuel tank temperature sensor). Refer to Exploded View.
CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR

Check the EVAP control system pressure sensor. Refer to Component Inspection.

Is the inspection result normal?
YES >>
GO TO 16.
NO >>
Replace EVAP control system pressure sensor. Refer to Exploded View.
CHECK EVAP PURGE LINE

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

Refer to System Description.

Is the inspection result normal?
YES >>
GO TO 17.
NO >>
Repair or reconnect the hose.
CLEAN EVAP PURGE LINE

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

>>
GO TO 18.
CHECK EVAP/ORVR LINE

Check EVAP/ORVR line between EVAP canister and fuel tank for clogging, kink, looseness and improper connection. For location, refer to Diagnosis Procedure.

Is the inspection result normal?
YES >>
GO TO 19.
NO >>
Repair or replace hoses and tubes.
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 Exploded View.
CHECK REFUELING EVAP VAPOR CUT VALVE

Check the refueling EVAP vapor cut valve. Refer to Component Inspection.

Is the inspection result normal?
YES >>
GO TO 21.
NO >>
Replace refueling EVAP vapor cut valve with fuel tank. Refer to Removal and Installation.
CHECK FUEL LEVEL SENSOR

Check the fuel level sensor. Refer to DTC Description.

Is the inspection result normal?
YES >>
INSPECTION END
NO >>
Replace fuel level sensor unit. Refer to Exploded View.

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