Temperature & Rpm Controlled Vacuum Solenoid

This solenoid is controlled by temperature sensor mounted in intake manifold coolant passage and by engine speed switch. When coolant temperature is below 113°F (45°C) or if engine is above 3000 RPM, solenoid valve closes vacuum to vacuum control valve and to first stage of EGR valve. This prevents the EGR valve from operating when engine is cold and improves cold driveability and engine performance above 3000 RPM.