Investigating P0455 on Your 2022 Subaru Forester
A P0455 on your 2022 Forester means the ECM detected a large leak in the EVAP system—equivalent to a hole of 0.040 inches or larger. Your Forester's 2.5L boxer engine and Symmetrical AWD aren't affected, but the code needs attention. Gas cap is the #1 suspect.
Clues and Symptoms
- Check engine light illuminated with P0455 stored
- Possible faint fuel odor near the rear
- Gas cap not clicking when tightened
- EVAP readiness monitor incomplete
Likely Culprits
- Gas Cap Seal (Very High Likelihood): Loose, cross-threaded, or worn seal. Most common cause by far. $0–$25.
- Purge Control Solenoid (Medium Likelihood): Subaru's purge valve can stick open. $150–$280 installed.
- Vent Control Valve (Medium Likelihood): Fails to seal during testing. $120–$250 installed.
- Vapor Hose/Line (Low Likelihood): Cracked or disconnected. $80–$200 depending on location.
- Charcoal Canister (Low Likelihood): Saturated or cracked. $200–$400 installed.
Diagnostic Path
Start with the gas cap—tighten it and drive 2–3 days. If P0455 returns, a Subaru dealer can use SSM4 to run an EVAP leak test. Smoke testing pinpoints the exact leak location. The boxer engine layout means some EVAP components sit lower than conventional engines.
Warranty Situation
Your 2022 Forester's 3-year/36,000-mile basic warranty may still apply depending on mileage. The federal emissions warranty (8yr/80k) covers EVAP components through 2030. Check with your Subaru dealer.
Safe to Drive?
Yes. P0455 is a vapor leak code. Your Forester's 2.5L boxer, CVT, Symmetrical AWD, and EyeSight safety systems all function normally.