With GST

Disconnect hose from water separator.
Disconnect EVAP canister vent control valve harness connector.
Verify the following.

Fig 1: Air Passage Continuity Specification Chart
Courtesy of NISSAN MOTOR CO., U.S.A.

If the result is NG, go to "DIAGNOSTIC PROCEDURE " .

If the result is OK, go to "DIAGNOSTIC PROCEDURE " for DTC P0442 .

Fig 2: Checking Overall Function Of EVAP Canister Vent Control Valve Circuit
Courtesy of NISSAN MOTOR CO., U.S.A.