Air Injection: Description and Operation

Secondary air injection system

CAUTION: When performing repair work, especially due to the confined conditions in the engine compartment, pay attention to the following:
^ Route all types of lines (e.g. for fuel, hydraulics, EVAP system, coolant, refrigerant, brake fluid and vacuum) as well as electrical wiring so that the original positions are restored.
^ Ensure sufficient clearance to all moving or hot components.


Function
^ The secondary air injection system blows air behind the exhaust valves for 100 seconds during a cold start (+15- C to +35- C coolant temperature).
^ This produces an oxygen rich exhaust gas which initiates after burning and reduces the heating-up phase of the catalytic converter.
^ Activation is performed by the Control module -J220- via the Secondary Air Injection (AIR) pump relay -J299- to secondary air inlet valve (N112) (1) change-over and combination valve.
^ The secondary air pump motor is activated] this creates a pressure and opens the combination valve at 60 to 70 mbar 1).
^ After each subsequent engine start (up to max. 96° C engines temperature) the secondary air system will switch on for 10 seconds during idling and will be checked by On Board Diagnostic. The Oxygen sensor regulation must then be active.

(1) Depending on version.