Monitor Description

Pressure switching valve is stuck OFF (Closed) 

The pressure switching valve opens when the purge VSV opens while the vehicle is running. Then, the fuel tank pressure drops 2 mmHg or more when the pressure switching valve is normal. If the pressure does not change, the ECM interprets this as a malfunction. The ECM illuminates the MIL and sets a DTC (2 trip detection logic).

Pressure switching valve is stuck ON (Open) 

In order to depressurize the fuel tank, the pump module's vent valve is turned ON (close) when the purge VSV opens while the vehicle is running. After the fuel tank pressure drops 20 mmHg, the purge VSV closes. Then, the fuel tank pressure rises slightly when the pressure switching valve is normal. If the pressure rises quickly, the ECM interprets this as a malfunction. The ECM illuminates the MIL and sets a DTC (2 trip detection logic).