P043F

EVAP System Leak Detection Reference Orifice High Flow

EVAP / emissions Generic OBD-II Medium

What it means

P043F is an EVAP monitor code. During a leak-detection self-test the system measures flow through a calibrated reference orifice; P043F sets when that flow reads higher than expected, pointing to a leak or a fault in the leak-detection hardware. It affects fuel-vapor containment and emissions only — the engine still starts and runs normally.

Medium

Can I keep driving? Yes — this is an emissions and fuel-vapor code; the car starts and drives normally, but it will keep failing the EVAP monitor until repaired.

Real-world scan data

Seen in

286

scans in the past year

Found in

0.1%

of scans

0.1%

of scans that found faults

Appears alongside · share of P043F scans

P2401in 97.9% of scans

P2402in 97.2% of scans

P2419in 95.5% 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

Check-engine light on
Failed emissions test or incomplete EVAP monitor
Occasional faint fuel-vapor smell near the tank
No noticeable change in how the engine runs

Common causes

Most likely first

Loose, missing, or incorrect fuel filler capLikely
Leak in an EVAP hose, the charcoal canister, or a connectionCommon
Fault or restriction in the leak-detection pump / reference-orifice assemblyCommon
Small leak at the fuel tank or filler neckLess often

How to diagnose & fix

Work through it in order

Check the fuel cap first — tighten, clean, or replace it if loose, wrong, or damaged, then clear and re-test.
Smoke-test the EVAP system to pinpoint leaks in hoses, the canister, and connections.
Inspect the leak-detection pump and reference orifice (and its filter) for faults or restriction.
Repair any leak found, clear the code, then complete a drive cycle so the EVAP monitor can re-run.

FAQ

Quick answers

Is it safe to drive with P043F?+

Yes — it's an emissions and vapor-containment fault, not a mechanical one. The car drives and starts normally, but expect a failed emissions test until it's fixed.

Can I just clear P043F?+

You can, but it returns after the EVAP monitor runs again unless the leak or hardware fault is actually repaired. Start with the fuel cap.

Read & clear P043F 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