Air Injection: Description and Operation

Secondary Air Injection, Function

Air is blown behind the exhaust valves by the Secondary Air Injection (AIR) system for a maximum of 100 seconds following cold start (coolant temperature of +5 °C to +33 °C). This adds oxygen to the exhaust, initiating a secondary combustion and thereby shortening the warm-up phase of the catalytic converter. Activation is triggered by the Motronic Engine Control Module (ECM) -J220- and sent via the Secondary Air Injection (AIR) pump relay -J299- to the Secondary Air Injection (AIR) solenoid valve -N112- (Change-over valve) and the combination valve.