Secondary Air Injection System
WARNING: This page is about a different car, the 2002 Audi S4. However, it is still accessible from the selected car via links, so may be relevant.
Due to over-enrichment of the mixture during cold start, an increased amount of unburned hydrocarbons exists in the exhaust gas. Injection of secondary air improves oxidation in the catalytic converter, speeding up start-up time for catalytic converter, and reducing emissions during cold start-up.
Secondary air injection system components include:
- Secondary air injection solenoid valve.
- Secondary air injection pump motor.
- Secondary air injection combination valve(s).
- Secondary air injection pump relay.
- Various hoses, check valves, wiring and harness connectors.
To test secondary Air Injection (AIR) system components, see secondary AIR related DTC(s) under DIAGNOSTIC TROUBLE CODE DEFINITIONS in appropriate SELF-DIAGNOSTICS article.