Monitor Description

Pressure Discharge Valve Open/Close Stuck Detection (Integral Term Method) 

If the difference in the fuel pump discharge amount feedback is equal to or above the threshold when the pressure discharge valve is opened and closed during normal driving, it is determined that there is a pressure discharge valve stuck malfunction. The ECM illuminates the MIL and stores a DTC.

Pressure Discharge Valve Open/Close Stuck Detection (Pressure Discharge Valve Active Method) 

If there is no change in the fuel pressure even when the pressure discharge valve is forcibly opened, it is determined that there is a pressure discharge valve stuck malfunction. The ECM illuminates the MIL and stores a DTC.