DTC P0411 Audi
Secondary Air Injection System Upstream Flow Detected
Secondary Air Injection System Upstream Flow Detected
Description
Engine started, battery voltage must be at least 11.5v, all electrical components must be off, parking brake must be engaged (to keep daytime driving lights off), automatic transmission selector must be in park and the ground between the engine and the chassis must be well connected. The ECM detected the Secondary AIR pump airflow was not diverted correctly when requested during the self-test. The pump is functioning but the quantity of air is recognized as insufficient by HO2S. Note: The solenoid valve is closed when no voltage is present.
Cause and Solution
Air pump output is blocked or restricted
AIR bypass solenoid is leaking or it is restricted
AIR bypass solenoid is stuck open or stuck closed
Check valve (one or more) is damaged or leaking
Electric air injection pump hose(s) leaking
Electric air injection pump is damaged or faulty
Video Guide
Diagnostic Info
- DTC Code: P0411
- Brand: Audi