Infiniti Q45. Manual - part 484

DTC P1491 VACUUM CUT VALVE BYPASS VALVE

EC-575

C

D

E

F

G

H

I

J

K

L

M

A

EC

3. 

CHECK VACUUM CUT VALVE BYPASS VALVE OPERATION

 Without CONSULT-II

1.

Turn ignition switch OFF.

2.

Remove vacuum cut valve and vacuum cut valve bypass valve as an assembly.

3.

Apply vacuum to port A and check that there is no suction from port B.

4.

Apply vacuum to port B and check that there is suction from port A.

5.

Blow air in port B and check that there is a resistance to flow out of port A.

6.

Disconnect vacuum cut valve bypass valve harness connector.

7.

Supply battery voltage to the terminal.

8.

Blow air in port A and check that air flows freely out of port B.

9.

Blow air in port B and check that air flows freely out of port A.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 7.

4. 

CHECK EVAP PURGE LINE

Check EVAP purge line between EVAP canister and fuel tank for clogging or disconnection.
OK or NG

OK

>> GO TO 5.

NG

>> Repair it.

5. 

CHECK EVAP PURGE PORT

Check EVAP purge port of fuel tank for clogging.
OK or NG

OK

>> GO TO 6.

NG

>> Clean EVAP purge port.

6. 

CHECK EVAP CANISTER

1.

Pinch the fresh air hose.

2.

Blow air into port A  and check that it flows freely out of port B .

OK or NG

OK

>> GO TO 12.

NG

>> Replace EVAP canister.

PBIB0635E

AEC630A

EC-576

DTC P1491 VACUUM CUT VALVE BYPASS VALVE

7. 

CHECK BYPASS HOSE

Check bypass hoses for clogging.

OK or NG

OK

>> GO TO 8.

NG

>> Repair or replace hoses.

8. 

CHECK VACUUM CUT VALVE BYPASS VALVE

Refer to 

EC-577, "Component Inspection"

 .

OK or NG

OK

>> GO TO 9.

NG

>> Replace vacuum cut valve bypass valve.

9. 

CHECK VACUUM CUT VALVE

Refer to 

EC-577, "Component Inspection"

 .

OK or NG

OK

>> GO TO 10.

NG

>> Replace vacuum cut valve.

10. 

CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR HOSE

1.

Turn ignition switch OFF.

2.

Check disconnection or improper connection of hose connected to EVAP control system pressure sensor.

OK or NG

OK

>> GO TO 11.

NG

>> Repair or replace.

11. 

CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR CONNECTOR

1.

Disconnect EVAP control system pressure sensor harness connector.

2.

Check connectors for water.

OK or NG

OK

>> GO TO 12.

NG

>> Replace EVAP control system pressure sensor.

12. 

CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR

Refer to 

EC-450, "Component Inspection"

 .

OK or NG

OK

>> GO TO 13.

NG

>> Replace EVAP control system pressure sensor.

13. 

CHECK RUBBER TUBE FOR CLOGGING

1.

Disconnect rubber tube connected to EVAP canister vent control valve.

2.

Check the rubber tube for clogging.

OK or NG

OK

>> GO TO 14.

NG

>> Clean the rubber tube using an air blower.

Water should not exist.

DTC P1491 VACUUM CUT VALVE BYPASS VALVE

EC-577

C

D

E

F

G

H

I

J

K

L

M

A

EC

14. 

CHECK EVAP CANISTER VENT CONTROL VALVE

Refer to 

EC-428, "Component Inspection"

 .

OK or NG

OK

>> GO TO 15.

NG

>> Replace EVAP canister vent control valve.

15. 

CHECK REFUELING EVAP VAPOR CUT VALVE

Refer to 

EC-41, "Component Inspection"

 .

OK or NG

OK

>> GO TO 16.

NG

>> Replace fuel tank.

16. 

CHECK REFUELING CONTROL VALVE

Refer to 

EC-41, "Component Inspection"

 .

OK or NG

OK

>> GO TO 17.

NG

>> Replace fuel tank.

17. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-145, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

>> INSPECTION END

Component Inspection

NBS0023U

VACUUM CUT VALVE BYPASS VALVE

 With CONSULT-II

1.

Reconnect all harness connectors disconnected.

2.

Turn ignition switch ON.

3.

Perform “VC/V BYPASS/V” in “ACTIVE TEST” mode.

4.

Check air passage continuity and operation delay time under the
following conditions.

Operation takes less than 1 second.

PBIB3138E

Condition

VC/V BYPASS/V

Air passage continuity 

between A and B

ON

Yes

OFF

No

PBIB0149E

EC-578

DTC P1491 VACUUM CUT VALVE BYPASS VALVE

 With GST

Check air passage continuity and operation delay time under the fol-
lowing conditions.

Operation takes less than 1 second.

VACUUM CUT VALVE

Check vacuum cut valve as follows:

●

Plug port C  and D  with fingers.

●

Apply vacuum to port A  and check that there is no suction from
port B .

●

Apply vacuum to port B  and check that there is suction from
port A .

●

Blow air in port B  and check that there is a resistance to flow out
of port A .

●

Open port C  and D .

●

Blow air in port A  check that air flows freely out of port C .

●

Blow air in port B  check that air flows freely out of port D .

Condition

Air passage continuity 

between A and B

12V direct current supply between 
terminals 1 and 2

Yes

No supply

No

PBIB0160E

SEF379Q