P0456 on Your 2019 Mazda3: First Year Investigation
Your 2019 Mazda3 (4th generation, BP—first year of the redesign) has triggered P0456—a very small EVAP leak. The 2.5L Skyactiv-G uses a standard EVAP system. Basic warranty expired. Federal emissions (8yr/80k) covers through 2027.
Clues
- Check engine light on
- P0456 stored
- No performance symptoms
- Gas cap may show wear after 6+ years
Suspects
- Gas Cap Seal (High Likelihood): Six years of wear. $10–$15.
- Purge Solenoid Valve (High Likelihood): Age-related. Under emissions warranty or $80–$180.
- Canister Vent Valve (Medium Likelihood): Wear. Under emissions warranty or $90–$200.
- EVAP Hose (Medium Likelihood): Rubber aging. $100–$210.
- Charcoal Canister (Low Likelihood): Fuel overfilling. $180–$340.
Diagnostic Steps
- Replace gas cap—$10–$15
- Clear code, drive 2–3 cycles
- Check federal emissions—8yr/80k through 2027
- Mazda dealer or independent shop
- Smoke test if needed ($80–$130)
Costs
- Gas cap: $10–$15
- Purge valve: $80–$180
- Federal emissions 8yr/80k through 2027
Can I Drive?
Yes. P0456 has zero impact on the Skyactiv or AWD.
Warranty
Basic 3yr/36k expired. Federal emissions 8yr/80k covers EVAP through 2027. First year of the 4th gen—ask about TSBs.