Water can enter the EGR vacuum modulator valve through the vacuum line, which can occur if the line is not properly sealed or if the EGR valve itself is leaking. Water can also enter the valve if the vehicle is driven through deep water, such as a flooded road.
To prevent water from entering the EGR vacuum modulator valve, make sure that the vacuum line is properly sealed and that the EGR valve is not leaking. If the vehicle is driven through deep water, be sure to dry it off thoroughly as soon as possible. If water does get into the valve, it should be replaced as soon as possible to prevent further damage.
