Possible Causes

WARNING: This page is about a different car, the 2002 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.

Malfunction is detected when an improper voltage signal is sent to ECM from EVAP-CSPS. Possible causes are:

EVAP-CSPS circuit open or shorted.
EVAP-CSPS hose clogged, kinked, leaking, disconnected or improperly connected.
Defective EVAP-CSPS.
Defective EVAP Canister Vent Control Valve (EVAP-CVCV).
Defective EVAP Canister Purge Volume Control Solenoid Valve (EVAP-CPVCSV).
Defective EVAP canister.
Defective hose between EVAP-CVCV and water separator.