Infiniti Q45. Manual - part 482

DTC P1490 VACUUM CUT VALVE BYPASS VALVE

EC-567

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3. 

CHECK VACUUM CUT VALVE BYPASS VALVE POWER SUPPLY CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect vacuum cut valve bypass valve harness connector.

3.

Turn ignition switch ON.

4.

Check voltage between vacuum cut valve bypass valve terminal
1 and ground with CONSULT-II or tester.

OK or NG

OK

>> GO TO 5.

NG

>> GO TO 4.

4. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors B401, B251

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Harness connectors B209, M139

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Harness connectors M135, F105

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

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

5. 

CHECK VACUUM CUT VALVE BYPASS VALVE OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check harness continuity between ECM terminal 112 and vacuum cut valve bypass valve terminal 2.
Refer to Wiring Diagram.

4.

Also check harness for short to ground and short to power.

OK or NG

OK

>> GO TO 7.

NG

>> GO TO 6.

Voltage: Battery voltage

PBIB0026E

PBIB0158E

Continuity should exist.

EC-568

DTC P1490 VACUUM CUT VALVE BYPASS VALVE

6. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors B401, B251

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Harness connectors B211, M141

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Harness connectors M135, F105

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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-568, "Component Inspection"

 .

OK or NG

OK

>> GO TO 8.

NG

>> Replace vacuum cut valve bypass valve.

8. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-145, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

>> INSPECTION END

Component Inspection

NBS0023M

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

DTC P1490 VACUUM CUT VALVE BYPASS VALVE

EC-569

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 With GST

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

Operation takes less than 1 second.

Condition

Air passage continuity 

between A and B

12V direct current supply between 
terminals 1 and 2

Yes

No supply

No

PBIB0160E

EC-570

DTC P1491 VACUUM CUT VALVE BYPASS VALVE

DTC P1491 VACUUM CUT VALVE BYPASS VALVE

PFP:17372

Description

NBS0023N

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

NBS0023O

Specification data are reference values.

PBIB0026E

SEF323U

MONITOR ITEM

CONDITION

SPECIFICATION

VC/V BYPASS/V

●

Ignition switch: ON

OFF