Infiniti M45 (Y34). Manual — part 475

DTC P1490 VACUUM CUT VALVE BYPASS VALVE

EC-589

C

D

E

F

G

H

I

J

K

L

M

A

EC

6.

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors B401, B251

●

Harness connectors B211, M141

●

Harness connectors M135, F105

●

Harness for open or short between vacuum cut valve bypass valve and ECM

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

7.

CHECK VACUUM CUT VALVE BYPASS VALVE

Refer to

EC-589, "Component Inspection"

.

OK or NG

OK

>> GO TO 8.

NG

>> Replace vacuum cut valve bypass valve.

8.

CHECK INTERMITTENT INCIDENT

Refer to

EC-132, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

.

>> INSPECTION END

Component Inspection

ABS002RN

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.

With GST

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

Operation takes less than 1 second.

Condition

VC/V BYPASS/V

Air passage continuity

between A and B

ON

Yes

OFF

No

PBIB0159E

Condition

Air passage continuity

between A and B

12V direct current supply between
terminals 1 and 2

Yes

No supply

No

PBIB0160E

EC-590

DTC P1491 VACUUM CUT VALVE BYPASS VALVE

DTC P1491 VACUUM CUT VALVE BYPASS VALVE

PFP:17372

Description

ABS002RO

COMPONENT DESCRIPTION

The vacuum cut valve and vacuum cut valve bypass valve are installed in parallel on the EVAP purge line
between the fuel tank and the EVAP canister.
The vacuum cut valve prevents the intake manifold vacuum from being applied to the fuel tank.
The vacuum cut valve bypass valve is a solenoid type valve and generally remains closed. It opens only for on
board diagnosis.
The vacuum cut valve bypass valve responds to signals from the ECM. When the ECM sends an ON (ground)
signal, the valve is opened. The vacuum cut valve is then bypassed to apply intake manifold vacuum to the
fuel tank.

EVAPORATIVE EMISSION SYSTEM DIAGRAM

CONSULT-II Reference Value in Data Monitor Mode

ABS002RP

Specification data are reference values.

PBIB0026E

SEF323U

MONITOR ITEM

CONDITION

SPECIFICATION

VC/V BYPAS S/V

●

Ignition switch: ON

OFF

DTC P1491 VACUUM CUT VALVE BYPASS VALVE

EC-591

C

D

E

F

G

H

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M

A

EC

On Board Diagnosis Logic

ABS002RQ

DTC Confirmation Procedure

ABS002RS

CAUTION:

Always drive vehicle at a safe speed.

NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:

●

Always perform test at a temperature of 5 to 30

°

C (41 to 86

°

F).

●

Before performing the following procedure, confirm that battery voltage is more than 11V at idle.

WITH CONSULT-II

1.

Turn ignition switch ON.

2.

Start engine and warm it up to normal operating temperature.

3.

Turn ignition switch OFF and wait at least 10 seconds.

4.

Start engine and let it idle for at least 70 seconds.

5.

Select “VC CUT/V BP/V P1491” of “EVAPORATIVE SYSTEM” in “DTC WORK SUPPORT” mode with
CONSULT-II.

6.

Touch “START”.

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P1491
1491

Vacuum cut valve bypass
valve

Vacuum cut valve bypass valve dose not
operate properly.

●

Vacuum cut valve bypass valve

●

Vacuum cut valve

●

Bypass hoses for clogging

●

EVAP control system pressure sensor
and circuit

●

EVAP canister vent control valve

●

Hose between fuel tank and vacuum cut
valve clogged

●

Hose between vacuum cut valve and
EVAP canister clogged

●

EVAP canister

●

EVAP purge port of fuel tank for clogging

●

Refueling purge EVAP vapor cut valve

●

Refueling control valve

SEF210Y

EC-592

DTC P1491 VACUUM CUT VALVE BYPASS VALVE

7.

When the following conditions are met, “TESTING” will be dis-
played on the CONSULT-II screen. Maintain the conditions con-
tinuously until “TESTING” changes to “COMPLETED”. (It will
take at least 30 seconds.)

If “TESTING” is not displayed after 5 minutes, retry from
step 3.

8.

Make sure that “OK” is displayed after touching “SELF-DIAG
RESULTS”. If “NG” is displayed, refer to

EC-595, "Diagnostic

Procedure"

.

ENG SPEED

More than 1,000 rpm

Selector lever

Suitable position

VHCL SPEED SE

More than 37 km/h (23 MPH)

B/FUEL SCHDL

1.0 - 10.0 msec

SEF211Y

SEF239Y