What does code P0456 mean on a Subaru and is it safe to drive?
P0456: Evaporative Emission System Leak Detected (Very Small Leak). Here's what it means on your Subaru, what usually causes it, what repairs typically cost, and how safe it is to keep driving.
What this code means
The EVAP system has detected a very small leak—often smaller than P0442. Commonly caused by a loose fuel cap or hairline crack in a hose.
Common causes for your Subaru
- Loose or worn gas cap seal
- Hairline crack in EVAP hoses
- Minor leak at purge or vent valve fittings
Symptoms
- Check Engine Light only
- Usually no noticeable driving symptoms
Typical fixes
- Inspect and replace gas cap if seal is hardened or cracked
- Smoke-test EVAP system to locate tiny leaks
- Repair or replace leaking hoses and fittings
Repair cost range
For a Subaru, repairs for P0456 often fall between $25 and $350, depending on the cause and whether you use OEM or aftermarket parts. Labor rates vary by location.
Known issues on Subaru
Subaru P0456 on older EJ-engine models often traces to the gas cap or a small crack in the EVAP canister vent hose. The canister is mounted low on AWD models and vulnerable to impact. Smoke test the canister assembly after confirming the cap is good.
Most commonly affected models