The main function of the compressor bypass valve is to allow the escape of pressure during the segment of operation when the throttle plate is closed. Without the presence of the valve to allow the pressure to be rerouted, the pressurized air would simply crash into the plate, build up, and eventually be repelled back into the turbo.
How do Air Injection System Air Bypass Valves work? The air bypass valve is installed on the secondary air pump, or inside a line from the secondary air pump to the intake manifold. When the valve is opened, the air pressure generated by the air pump will be sent into the engine instead of the exhaust.