Symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

Possible Causes

- Damage harness or connectors to the Purge Control Valve - The valve circuit is open or shorted - EVAP canister vent control valve may be faulty

When Detected

An improper voltage signal is sent to ECM through EVAP canister vent control valve.

Tech Notes

Before replacing any parts, check for damage EVAP canister and for loose hoses from the vent control valve to the canister. There is a bulletin available for 2002-2005 Nissan Altima

Description

The EVAP canister vent control valve is located on the EVAP canister and is used to seal the canister vent. This solenoid (the EVAP canister vent control valve) responds to signals from the ECM. When the ECM sends an ON signal, the coil in the solenoid valve is energized. A plunger will then move to seal the canister vent. The ability to seal the vent is necessary for the on board diagnosis of other evaporative emission control system components. This solenoid valve is used only for diagnosis, and usually remains opened. When the vent is closed, under normal purge conditions, the evaporative emission control system is depressurized and allows EVAP Control System (Small Leak) diagnosis.