What does this code p0411 means?

The code P0411 refers to "Secondary Air Injection System Incorrect Flow Detected." This diagnostic trouble code (DTC) indicates that the vehicle's onboard diagnostic system has detected a problem with the secondary air injection system, which is responsible for introducing air into the exhaust stream to help reduce emissions during cold starts. Common causes for this code can include a malfunctioning air pump, blocked hoses, or issues with the control valves. Addressing this issue typically involves inspecting the components of the secondary air system to identify and rectify any faults.