P0411 — Secondary Air Injection System Incorrect Flow Detected
Category: Powertrain Severity: Medium
Updated:
DTC code P0411 means: Secondary Air Injection System Incorrect Flow Detected. It falls under the "Powertrain" category, with an estimated severity of Medium. Common causes include secondary air passages clogged with carbon, weak pump and stuck cut-off valve; it's worth confirming the diagnosis before replacing parts.
Possible causes
- Secondary air passages clogged with carbon
- Weak pump
- Stuck cut-off valve
- Leaking hoses
Symptoms
- Check engine light
- No drivability symptoms
How to diagnose it step by step
- Check the pump is blowing.
- Check the cut-off valve.
- Inspect passages and hoses.
- Clean or replace as needed.
How to fix it
Check pump flow and valve opening; on many engines (VW, Toyota) the cylinder head passages clog and must be cleaned.
Estimated repair cost
$150–650.
Frequently asked questions
What does DTC code P0411 mean?
Secondary Air Injection System Incorrect Flow Detected.
Is code P0411 serious?
Severity Medium. Not urgent, but worth diagnosing to avoid bigger damage.
Can I keep driving with code P0411?
Yes, it is safe to drive.
Related codes
P0410 P0406 P0405 P0404 P0403 P0402 P0420 P0401 P0421 P0400
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