Secondary Air Injection Sensor 1 -G609-, Checking: Function

The secondary air injection system blows air into the exhaust, behind the exhaust valves, via a passage in the cylinder head. The "pressure based secondary air diagnostics" function is used. In this system, the signal from Secondary Air Injection Sensor 1 -G609- is evaluated in the engine control module. The injected air quantity is determined from the pressure level. This extra air injection takes place on a cold-start of the engine for about 45 - 100 s and serves to quickly heat the catalytic convertor(s) for improved emissions.

Special Tools And Workshop Equipment Required 

• Multimeter
• Wiring Diagram
• Scan Tool