ACDelco GM Original Equipment EGR Valve Control Solenoids control the EGR system and are GM-recommended replacements for your vehicle's original components. When the EGR control solenoids are activated, a passage is opened that allows exhaust gases into the intake manifold. The EGR solenoid is controlled by the engine computer and is activated at a very specific time in order to achieve the best performance, efficiency, and emissions from the engine. These original equipment EGR valve control solenoids have been manufactured to fit your GM vehicle, providing the same performance, durability, and service life you expect from General Motors.