What causes a P0411 code?

P0411 can be triggered by several issues — see the verified probable causes and step-by-step diagnostics shared by mechanics and owners on OBDIY.

Can I drive with a P0411 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P0411 active.

Follow the step-by-step diagnostic on this page, then read the verified fixes contributed by other Heavy Truck owners — the answer marked "Verified Cause" worked for the original poster.

OBDIY

OBD-II

P0411

P0411 Secondary Air Injection System Incorrect Flow

What it means

Detected on legacy light/medium-duty trucks or specialized vocational Cummins engines, indicating that the air injection system is failing to deliver the required oxygen to the exhaust during cold start.