Investigating P0455 on Your 2021 Ford Bronco Sport
A P0455 on your 2021 Ford Bronco Sport means the PCM detected a large EVAP leak. Your Bronco Sport—built on the Escape platform with a 1.5L or 2.0L EcoBoost—is out of Ford's basic warranty but covered by the federal emissions warranty. The gas cap is the #1 suspect.
Symptoms Present
- Check engine light with P0455
- Faint fuel odor near the rear
- Gas cap seal wearing after 4+ years
- Failed emissions test
Causes Ranked
- Gas Cap Seal (Very High Likelihood): Worn rubber seal. Replace for $10–$25. The most common fix.
- Canister Vent Solenoid (Medium Likelihood): Ford's vent solenoid sticking open. $120–$220.
- EVAP Purge Valve (Medium Likelihood): Stuck open or leaking. $100–$200.
- Vapor Line Crack (Low Likelihood): Hose deterioration under the vehicle. $80–$200.
- Charcoal Canister (Low Likelihood): Saturated from fuel overfilling. $200–$350.
Diagnostic Path
Replace the gas cap with an OEM Ford cap ($10–$25), clear the code, and drive 2–3 cycles. If P0455 returns, a Ford dealer will smoke-test the system. For Bronco Sports used on unpaved roads, inspect underside vapor lines for damage.
Warranty Coverage
Ford's basic warranty (3 years/36,000 miles) has expired. The federal emissions warranty (8 years/80,000 miles) covers EVAP through 2029. Contact your dealer for mileage verification.
Safe to Drive?
Yes. P0455 doesn't affect the Bronco Sport's engine, AWD system, or any driving dynamics.