System: Powertrain (P-Code)
SAE Standard (Generic)
Family: Secondary Air Injection System
Code P0411: AIR System A Incorrect Flow Detected
Diagnostic & Technical Explanation
Code P0411 (AIR System A Incorrect Flow Detected) sets when the ECM commands the secondary air injection system (used to inject fresh air into the exhaust during cold start to speed catalyst light-off and reduce emissions) and detects incorrect flow, an open/shorted switching valve circuit, or a control circuit fault. Causes are a seized or failed AIR pump, a stuck or corroded switching/check valve, a collapsed or leaking air delivery hose, or damaged wiring to the pump/valve.
First-listed procedure
Rank #1
Inspect AIR delivery hoses and check valves
Easy DIY
This is the first procedure in the authored
consideration order, not a measured cause likelihood. Execute it only when its prerequisites
and diagnostic findings support it. Its cost and labor estimates (where known), the step-by-step procedure and the
remaining 3 procedure(s) are in the licensed dataset. Ordering context.
Full family: Secondary Air Injection System
What this page does not show
This page publishes the fault mechanism and the code index. The licensed dataset adds, for
every one of the 15,886 codes, the full authored repair set (56,729 procedures in total)
with the fields deliberately withheld here:
- Procedures 2..n after the first-listed procedure
- Aftermarket parts cost ranges in USD (
est_parts_cost_min/max_usd)
- Professional labor-hour estimates (
est_labor_hours)
- Step-by-step diagnostic and repair instructions
- Replacement-part mappings and catalog lookups
- 6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)