Air Injection: Description and Operation

Secondary Air Injection (AIR) system
Function
Air is blown behind the exhaust valves by the Secondary Air Injection (AIR) system for approximately 65 seconds during cold start (coolant temperature of +5 °C to +35 °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 approximately 5 seconds at idle and checked via the On Board Diagnostic (OBD).

WARNING: Observe the following for all installations, especially in engine compartment due to lack of room:
- Route lines of all types (e.g. for fuel, hydraulic, EVAP canister system, coolant and refrigerant, brake fluid, vacuum) and electrical wiring so that the original path is followed
- Watch for sufficient clearance to all moving or hot components.