Secondary Air Injection (AIR) system: 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. In addition, the Secondary Air Injection (AIR) system is switched on for 10 seconds during idle after every subsequent engine start (up to max. 96° C engine temperature) and is checked via On Board Diagnostic (OBD). Oxygen sensor control must be active for this.