Air Injection: Testing and Inspection

Secondary Air Injection System

=> [ Combination Valve for Secondary Air Injection, Checking Function and for Leaks ] Combination Valve For Secondary Air Injection, Checking Function and For Leaks

=> [ Secondary Air Injection Solenoid Valve, Checking ] Secondary Air Injection Solenoid Valve, Checking

=> [ Secondary Air Injection Solenoid Valve 2, Checking ] Secondary Air Injection Solenoid Valve 2, Checking

=> [ Secondary Air Injection Pump Motor, Checking ] Secondary Air Injection Pump Motor, Checking

=> [ Secondary Air Injection Sensor, Checking ] Secondary Air Injection Sensor, Checking

Principle

Due to the rich mixture during the cold start phase, the exhaust emissions contain an increased level of unburned hydrocarbons. The Secondary Air Injection (AIR) system improves the secondary oxidation within the catalytic converter, thereby reducing harmful emissions. The heat released by secondary oxidation shortens the start-up time of the catalytic converter considerably, as well as significantly improves emissions quality during the cold-running phase.

Function

• During cold start (with coolant temperatures +15 to +35 °C), the Secondary Air Injection (AIR) system blows air behind the exhaust valve for approx. 65 seconds. This produces an oxygen rich exhaust gas, causes the after burning and reduces the heating-up phase of the catalytic converter.

• In addition, the Secondary Air Injection (AIR) system is switched on with a delay of approx. 20 seconds during idle for 5 seconds after every subsequent engine start up to max. 80 °C coolant temperature and is checked by On Board Diagnostic (OBD).