Air Injection: Description and Operation

Function
The Secondary Air Injection (AIR) system directs air in behind the exhaust valve for approx. 30 seconds during a cold start (engine coolant temperature 15 ° to 35 °C or 59 ° to 95 °F). The extra air creates an oxygen-rich exhaust gas, increases after burning and reduces the heat-up time for the Three Way Catalytic Converter (TWC).

Activation is initiated by the Motronic Engine Control Module (ECM) J220, via the secondary air injection pump relay J299, to the secondary air injection solenoid valve N112, check valve and combi-valve. In addition to operating during cold-start, the AIR system is switched on at idle.

The secondary air injection system is checked by the On Board Diagnostic program (up to max. 60 °C or 140 °F engine coolant temperature).