P2279

Intake Air System Leak Bank 1

Fuel & air metering Generic OBD-II Medium

What it means

P2279 means the ECM has detected unmetered air entering the engine after the mass-air-flow sensor — an intake leak on bank 1. Because that extra air isn't measured, the mixture goes lean, causing rough idle, hesitation, and often lean fuel-trim codes. It's usually traced to a cracked intake boot, a loose clamp, or a split vacuum hose.

Medium

Can I keep driving? You can usually drive, but expect rough or high idle and hesitation; fix it soon so the lean mixture doesn't cause misfires or converter damage.

Real-world scan data

Seen in

568

scans in the past year

Found in

0.1%

of scans

0.2%

of scans that found faults

Appears alongside · share of P2279 scans

P068Ain 12.3% of scans

P0299in 11.8% of scans

P1102in 10.2% of scans

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

Rough, high, or unstable idle
Hesitation or stumble on light acceleration
Hissing or whistling from the intake
Check-engine light, often with lean codes (P0171/P0174)
Slightly reduced fuel economy

Common causes

Most likely first

Cracked or split intake boot/hose between the MAF and throttle bodyLikely
Loose clamp or torn gasket letting unmetered air inCommon
Cracked or disconnected PCV or brake-booster vacuum hoseCommon
Leaking intake manifold gasket or throttle-body gasketLess often
Failed or leaking gasket at a sensor port on the intakeLess often

How to diagnose & fix

Work through it in order

Visually inspect all intake ducting between the MAF and engine for cracks, tears, and loose clamps.
Check the PCV hose and brake-booster hose for splits or disconnected ends.
Perform a smoke test of the intake to pinpoint the leak.
Spray a small amount of carb cleaner around intake joints at idle and listen for RPM change to locate the leak.
Replace the leaking boot, hose, or gasket, then clear and re-test.

FAQ

Quick answers

Is it safe to drive with P2279?+

Short-term, usually yes, but the engine is running lean. Extended lean operation can cause misfires and overheat the converter, so repair it promptly.

Can I just clear P2279?+

It will come back as soon as the engine sees the unmetered air again. The leak has to be sealed for the code to stay off.

Read & clear P2279 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