Air Injection: Description and Operation

Secondary air injection system, checking
Function
The Secondary air injection system injects air behind the exhaust valve for approximately 30 seconds, depending upon engine coolant temperature, load, RPM and air flow rate during the cold start (+5°C to +40°C engine coolant temperature).

Secondary air injection operation:
^ Produces an Oxygen rich exhaust
^ Causes after-burning
^ Reduces the duration of the three-way catalyst heat-up phase

Activation is initiated by the Motronic Engine Control Module (ECM) -J220- via the secondary air injection system pump relay -J299- to the solenoid valve and pneumatic valve.
In addition to the engine cold start warm up phase, the secondary air injection system is checked via On Board Diagnostic (OBD) (up to an 80°C engine coolant temperature, maximum).
If the readiness code is being created, engine coolant temperature can be above 80°C.