P2440

AIR System Switching Valve Stuck Open Bank 1

Q: Is it safe to drive with P2440?

Generally yes for short trips, but a valve stuck open lets air into the exhaust continuously, which can upset idle and fuel trims. Fix it to avoid running problems and to pass emissions.

Q: Can I just clear P2440?

It returns while the valve stays stuck open. The valve usually needs cleaning or replacement to clear it for good.

Secondary air injection (AIR) Generic OBD-II Medium

What it means

P2440 means the Bank 1 secondary-air switching valve is stuck open — it should only route air into the exhaust briefly at cold start, but it's staying open. That lets extra air reach the exhaust continuously, which can skew oxygen-sensor readings and fuel trims and upset the idle. The usual cause is carbon or debris jamming the valve, or a failed return spring or check valve.

Medium

Can I keep driving? Mostly yes — a stuck-open air valve can upset idle and fuel trims and will fail emissions; drivable, but fix it to avoid running problems.

Real-world scan data

Seen in

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Rough or unstable idle, especially once warm
Skewed fuel trims or false lean O2 readings
May fail an emissions/readiness check

Common causes

Most likely first

Switching/diverter valve stuck open by carbon or debrisLikely
Failed valve return spring or diaphragmCommon
Leaking check valve holding the valve openCommon
Vacuum control line or solenoid faultLess often
Corroded or seized valveLess often

How to diagnose & fix

Work through it in order

Inspect the AIR switching/diverter valve for carbon, debris, or sticking.
Check the vacuum control line and the control solenoid.
Test the check valve for leakage that could hold the valve open.
Clean or replace the stuck valve as needed.
Clear the code and re-test, watching live O2 and fuel-trim data.

FAQ

Quick answers

Is it safe to drive with P2440?+

Generally yes for short trips, but a valve stuck open lets air into the exhaust continuously, which can upset idle and fuel trims. Fix it to avoid running problems and to pass emissions.

Can I just clear P2440?+

It returns while the valve stays stuck open. The valve usually needs cleaning or replacement to clear it for good.

Read & clear P2440 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX