P2440: Secondary Air Switching Valve Stuck Open (Bank 1)
P2440 means the bank 1 secondary air shut-off valve stays open when the engine computer commands it closed. The car usually drives normally, but an open valve lets hot exhaust reach the air pump and can damage it, so it should be repaired soon.
You can drive, but get it checked soon
The engine normally runs fine and the code does not put the car into limp mode. But an open valve lets hot exhaust flow back toward the pump, which can wear it out or make it fail, and the emissions system is affected, so don't leave it for long.
What it means
The secondary air injection (AIR) system uses a pump to blow fresh air into the exhaust right after a cold start, which helps the emissions parts warm up and burn off leftover fuel. A switching valve (also called a shut-off valve) opens to let that air in and closes when the system is done. During a self-test, the computer runs the pump while commanding the valve closed and expects air pressure to build in the duct. If the pressure stays too low, it concludes the valve is stuck open and sets P2440. Bank 1 is the side of the engine that has cylinder number 1. The exact test limits differ by manufacturer, and the computer turns on the check engine light when the test fails. On some Toyota and Lexus trucks, debris from the pump has been known to jam the valve open.
Likely causes
- Valve held open by debris from a damaged pump filterVery likely
Pieces from a broken pump filter can lodge in the valve and keep it from sealing.
- Valve seat carboned up or corroded by condensatePossible
Soot buildup or rust from moisture in the system can stop the valve from closing tightly.
- Electric or vacuum actuator does not close the valvePossible
If the part that moves the valve fails, the valve cannot shut even when the computer commands it.
What you may notice
- Check engine light on, often after a cold start
- Air pump that is noisy or fails later because of exhaust backflow
- Often stored together with P2442 or P2445
What to check, cheapest first
- 1Read all stored codes and note whether P2442, P2445, P2441, P2444, P0411 or P0412 are also present, since they point to the same system. · you can do it
- 2Look over the air pump, hoses and wiring near the valve for cracks, loose connections, or damage. · you can do it
- 3Check the pump's air filter or intake for damage or missing pieces, which can show that debris reached the valve. · you can do it
- 4Test whether the valve's electric or vacuum actuator moves and holds when commanded. · mechanic
- 5Remove the valve and inspect it for debris, carbon buildup, or corrosion on the seat. · mechanic
- 6On engines with two banks, check both banks and the pump, then clear the code and run a drive cycle to confirm the repair. · mechanic
Related codes
Frequently asked questions
Can I drive with P2440?+
Usually yes for a short time, since the code does not cause limp mode. Have it fixed soon because exhaust backflow can damage the air pump.
Can a loose gas cap cause P2440?+
No. This code relates to the secondary air valve and its pressure test, not the fuel system or gas cap.
Will it pass an emissions test?+
Probably not. The check engine light is on and the code is emissions related, so the repair is generally needed first.
Written with the help of AI from the public OBDex definition (CC0). Each make may use the code differently. Updated: 2026-11-10