Secondary air system, function

During a cold start (+15 ° C to +35 ° C coolant temperature), the secondary air system blows air behind the exhaust valve for 65 seconds. This enriches the exhaust with oxygen, and starts after-burning, thereby reducing the catalytic converter warm-up phase. Control passes from the Motronic Engine Control Module (ECM) J220 across the Secondary Air Injection (AIR) Pump Relay J299 to the Secondary Air Injection (AIR) Solenoid Valve N112 and combination valve. In addition, on every subsequent start of the engine (up to a maximum engine temperature of 85 ° C), the secondary air system will idle for 5 seconds after a delay of about 20 seconds and the self-diagnosis is run.