P0411
Secondary Air Injection System Incorrect Flow Detected
This code means the engine's computer has detected that the secondary air injection system isn't flowing air correctly into the exhaust. This system helps reduce emissions by pumping fresh air into the exhaust during cold starts to help the catalytic converter warm up faster.
Secondary Air Injection System Incorrect Flow Detected
Common causes
- high
Faulty Air Pump
The electric air pump itself may have failed, preventing air from being pushed into the exhaust.
Typical part cost: $200-600 part
- medium
Stuck/Faulty Check Valve(s)
Check valves prevent exhaust gases from entering the air pump; if stuck open or closed, they disrupt flow.
Typical part cost: $50-150 part per valve
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First things to check
- 1Listen for the air pump operating during a cold start (it should run for a minute or two).
- 2Visually inspect all hoses, vacuum lines, and electrical connections related to the secondary air injection system.
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Related codes
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Frequently asked questions
What is the secondary air injection system for?
It's an emissions control system that pumps fresh air into the exhaust during cold starts to help burn off uncombusted fuel and warm up the catalytic converter faster, reducing harmful emissions.
Will a P0411 code cause my car to run poorly?
Typically, no. The secondary air injection system only operates for a short period during cold starts and does not directly impact engine performance once the engine is warm.
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