Investigating P0456 on Your 2021 Crosstrek
Your 2021 Crosstrek (2nd generation) has triggered P0456—a very small EVAP leak. The 2.0L or 2.5L Boxer with Symmetrical AWD uses a standard EVAP system. Basic warranty (3yr/36k) expired in 2024, but federal emissions (8yr/80k) covers EVAP through 2029.
Clues
- Check engine light on
- P0456 stored
- No performance symptoms
- Gas cap may show early wear
Suspects
- Gas Cap Seal (High Likelihood): Four years of wear. $10–$15.
- Purge Control Solenoid Valve (High Likelihood): Known Subaru failure point. Under emissions warranty or $90–$210.
- Canister Vent Valve (Medium Likelihood): Age-related. Under emissions warranty or $100–$230.
- EVAP Hose (Medium Likelihood): Rubber aging. $110–$240.
- Charcoal Canister (Low Likelihood): Fuel overfilling. $200–$380.
Diagnostic Steps
- Replace gas cap—$10–$15
- Clear code, drive 2–3 cycles
- Check federal emissions warranty—8yr/80k through 2029
- Dealer appointment—ask about EVAP TSBs
- Smoke test if needed ($80–$150)
Costs
- Gas cap: $10–$15
- Purge valve: $90–$210 (may be emissions warranty covered)
- Canister vent valve: $100–$230
- Federal emissions 8yr/80k through 2029
Can I Drive?
Yes. P0456 has zero impact on the Boxer engine, AWD, or safety systems.
Warranty
Basic 3yr/36k expired. Federal emissions 8yr/80k covers EVAP through 2029. 5yr/60k powertrain through 2026. Ask about applicable TSBs.