P0411

AIR System A Incorrect Flow Detected

Q: Is it safe to drive with P0411?

Yes — the secondary air system only works for a minute or two after a cold start, so driveability is unaffected. It will fail emissions until repaired.

Q: Can I just clear P0411?

It will return the next time the system self-tests on a cold start unless the airflow fault — usually a check valve or pump — is fixed.

Secondary air injection Generic OBD-II Medium

What it means

P0411 means the secondary air injection ("AIR") system isn't delivering the airflow the ECM expects into the exhaust — either too much or too little. That pump only runs for a short time after a cold start to speed up catalyst warm-up, so this won't affect how the car drives. It does keep the check-engine light on and will fail an emissions test.

Medium

Can I keep driving? Safe to drive — the air pump only runs briefly at cold start, so it won't change how the car drives, but it fails emissions and keeps the light on.

Real-world scan data

Seen in

119

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
Fails an emissions test
Sometimes a loud air-pump whir on cold start-up

Common causes

Most likely first

Stuck or leaking check valve letting exhaust back into the pumpLikely
Failed secondary air injection pump (often from water ingress)Common
Clogged or broken air injection hose or passageCommon
Faulty air switching/solenoid valve or its vacuum supplyLess often
Damaged wiring or connector in the systemLess often
Rarely, a failing ECMLess often

How to diagnose & fix

Work through it in order

Reproduce the fault on a cold start and listen for the pump running.
Inspect the check valve, hoses, and pipes for leaks, clogging, or carbon.
Test the air switching valve and solenoid actuation.
Confirm the pump builds airflow; replace it if seized or water-damaged.
Clear the carbon or replace the failed part, then clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0411?+

Yes — the secondary air system only works for a minute or two after a cold start, so driveability is unaffected. It will fail emissions until repaired.

Can I just clear P0411?+

It will return the next time the system self-tests on a cold start unless the airflow fault — usually a check valve or pump — is fixed.

Read & clear P0411 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