MasterTuning Fault code dictionary (DTC)

P0456 — Evaporative Emission System Very Small Leak Detected

Severity: Informational Can you drive? Yes, no known limitation Make: All makes (OBD-II standard)
MeaningYour car's computer has detected a very small leak in the system that captures and stores fuel vapors so they do not escape into the air. This usually means fuel tank pressure is dropping slower or faster than expected during self-testing.
FamilyPowertrain (P)

Typical symptoms

Check Engine light is on
You might smell fuel near the rear of the vehicle

Common causes

A loose, damaged, or worn fuel filler cap
A small crack in one of the rubber hoses connected to the EVAP system
A faulty vent valve or purge valve that is not sealing completely

What to do

Start by checking if your fuel cap is tightened properly and has no cracks on the rubber seal. It is not an emergency that will leave you stranded, but you should have it checked soon.

Frequently asked questions

What does code P0456 mean?

Evaporative Emission System Very Small Leak Detected. Your car's computer has detected a very small leak in the system that captures and stores fuel vapors so they do not escape into the air. This usually means fuel tank pressure is dropping slower or faster than expected during self-testing.

Can I keep driving with code P0456 active?

Yes, no known limitation

Common causes — P0456

A loose, damaged, or worn fuel filler cap A small crack in one of the rubber hoses connected to the EVAP system A faulty vent valve or purge valve that is not sealing completely

How do you fix code P0456?

Start by checking if your fuel cap is tightened properly and has no cracks on the rubber seal. It is not an emergency that will leave you stranded, but you should have it checked soon.

Need help with this fault?

We are ECU specialists: diagnosis, file repair and remapping for cars, bikes, trucks and agricultural vehicles.

Contact us
Where to get it fixed

Related codes