P0411 GMC Sierra 1500
Secondary Air Injection System Incorrect Flow Detected · Powertrain Code · Medium · Repair: Moderate
What is P0411?
The secondary air injection system is not flowing the expected amount of air.
When the GMC Sierra 1500 triggers code P0411 (secondary air injection system incorrect flow detected), it typically points to an issue in the powertrain system. Below you'll find the most common causes, symptoms, and repair options specific to the GMC Sierra 1500.
This repair is rated moderate, meaning some experience and specialty tools required.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your GMC Sierra 1500.
Common Causes on GMC Sierra 1500
- Incorrect airflow detected in secondary AIR system
- AIR pump producing insufficient flow due to wear
- Check valve leaking or stuck, allowing exhaust back into AIR pump
- Rusted or clogged AIR injection tubes in exhaust manifolds
- AIR pump relay providing intermittent power
Symptoms
- Check Engine Light on
- Typically no noticeable driveability symptoms
- May fail emissions inspection
Notes for GMC Sierra 1500
P0410 and P0411 often appear together on GM V8 trucks — replacing the pump, both check valves, and the relay as a kit is the most cost-effective repair.