P0456 on Your 2018 CX-5: The First KF
Your 2018 CX-5 (2nd generation, KF—second year) has triggered P0456—a very small EVAP leak. The 2.5L Skyactiv-G uses a standard EVAP system. All basic warranties expired. Federal emissions (8yr/80k) through 2026—last window.
Clues
- Check engine light on
- P0456 stored
- No performance symptoms
- Gas cap shows wear after 7+ years
Suspects
- Gas Cap Seal (High Likelihood): Seven years of wear. $10–$15.
- Purge Solenoid Valve (High Likelihood): Age-related. $80–$180.
- Canister Vent Valve (Medium Likelihood): Wear. $90–$200.
- EVAP Hose (Medium Likelihood): Rubber deterioration. $100–$210.
- Charcoal Canister (Low Likelihood): Fuel overfilling over years. $180–$340.
Diagnostic Steps
- Replace gas cap—$10–$15
- Clear code, drive 2–3 cycles
- Check federal emissions warranty—8yr/80k through 2026
- Smoke test if out-of-pocket ($80–$130)
Costs
- Gas cap: $10–$15
- Purge valve: $80–$180
- Canister vent valve: $90–$200
- Federal emissions through 2026—last window
Can I Drive?
Yes. P0456 has zero impact on the Skyactiv or AWD.
Warranty
All basic warranties expired. Federal emissions 8yr/80k through 2026—last window. Mazda EVAP repairs are affordable even out of pocket.