Investigating P0455 on Your 2020 Chevrolet Colorado
A P0455 on your 2020 Colorado means the ECM detected a large EVAP leak—equivalent to a 0.040-inch or larger opening. Your 2nd-generation Colorado with the 2.5L I4, 3.6L V6, or 2.8L Duramax diesel is out of GM's basic warranty but covered by the federal emissions warranty. The gas cap is the usual suspect.
Symptoms
- Check engine light with P0455
- Possible P0449 companion code
- Faint fuel odor near the bed
- Gas cap seal worn after 5+ years
- Failed emissions test
Causes Ranked
- Gas Cap Seal (Very High Likelihood): Worn seal. Replace for $10–$25.
- Vent Valve Solenoid (Medium Likelihood): GM's vent solenoid near the charcoal canister. $100–$200.
- Purge Solenoid (Medium Likelihood): Stuck open. $80–$180.
- Vapor Line (Low Likelihood): Cracked hose under the truck bed from road debris. $80–$200.
- Charcoal Canister (Low Likelihood): Saturated from overfilling. $200–$350.
Diagnostic Path
Replace the gas cap ($10–$25), clear the code, drive 2–3 cycles. If P0455 returns with P0449, replace the vent valve solenoid. On the Colorado, it's near the charcoal canister under the bed.
Warranty Coverage
GM's basic warranty (3yr/36k) has expired. The federal emissions warranty (8yr/80k) covers EVAP through 2028. Contact your dealer for mileage verification.
Safe to Drive?
Yes. P0455 doesn't affect the Colorado's engine, transmission, towing, or 4x4.