P0411

Secondary Air Injection System Incorrect Flow Detected

OBD-II diagnostic trouble code P0411indicates a fault detected by the vehicle's onboard computer. This code applies to all OBD-II compliant vehicles and should be addressed promptly to avoid potential engine or emissions system damage.

Severity Level 3 — Moderate

This code indicates a moderate issue that may affect vehicle performance and fuel economy. Continued driving is possible in most cases, but prompt diagnosis and repair are recommended to prevent further damage.

Common Symptoms

• Check Engine Light on (usually only symptom)
• Failed emissions test
• No driveability issues in most cases
• Air pump may run continuously or not at all

Possible Causes

• Failed secondary air pump — bearings worn out, motor draws high current and blows fuse
• Leaking or disconnected air injection hose
• Faulty combination/check valve — stuck open (allows exhaust into pump, destroying it) or stuck closed
• Faulty secondary air injection control solenoid
• Clogged air passages in cylinder head

Common Fixes

• Replace secondary air injection pump ($300-800)
• Replace leaking hoses in secondary air system ($30-200)
• Replace combination valve — do this preventively when replacing pump ($80-300)
• Replace control solenoid ($50-200)
• Clean carbon from air injection passages ($300-800)

Estimated Repair Cost

These are estimated costs based on generic repair data. Actual costs may vary depending on your vehicle, location, and labor rates.

Explore Repair Costs

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