What causes a P2440 code?

P2440 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 P2440 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P2440 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

P2440

Secondary Air Injection System Switching Valve Stuck Open Bank 1

What it means

The Engine Control Module has detected that the secondary air injection switching valve is stuck in the open position, potentially allowing exhaust gases to flow back into the air pump system.