2018 Mazda CX-5 P0455: Large EVAP Leak Repair

Diagnosing P0455 on Your 2018 Mazda CX-5

P0455 on your 2018 CX-5 means a large EVAP leak. At 6+ years old, rubber seals and gaskets are prime suspects. Gas cap is the starting point.

Symptoms

• Check engine light on
• P0455 stored
• Fuel smell possible
• Emissions test failure

Causes Ranked

1. Gas Cap Seal (Very High Likelihood): 6+ years of wear. $10–$20.
2. Purge Solenoid Valve (Medium Likelihood): Age-related failure. $120–$240 installed.
3. Canister Vent Valve (Medium Likelihood): Worn seals. $110–$230 installed.
4. Vapor Hoses (Low-Medium Likelihood): Heat/age cracking. $70–$180.
5. Charcoal Canister (Low Likelihood): Saturated from overfilling. $180–$350 installed.

DIY Approach

Gas cap: easy. Purge solenoid: moderate—accessible on the SKYACTIV 2.5L. Vent valve: near the canister, may require lifting the vehicle. Smoke test ($80–$150) confirms the leak.

Warranty

Basic warranty expired. Federal emissions (8yr/80k) covers EVAP through 2026—last chance. Act now.

Safe to Drive?

Yes. P0455 is vapor only.

Frequently Asked Questions