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.
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.
Related codes
Often seen with P043F
Read & clear P043F yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX