Air Injection System: Operation
When exhaust system pressure is less than atmospheric pressure, reed valve is opened to incoming air. When exhaust pressure exceeds atmospheric pressure, reed valve is closed to incoming air. This valve also acts as a check valve.
On GLC (Federal) and 626 models, air is drawn into exhaust system downstream of the front catalytic converter. The air control valve(s) governs the injection of additional air upstream of the converter to help reduce emissions.