Diagnosing P0455 on Your 2023 Chevrolet Suburban
A P0455 on your 2023 Suburban means the ECM detected a large EVAP leak. Your 12th-generation T1-platform Suburban with the 5.3L V8, 6.2L V8, or 3.0L Duramax diesel is under warranty. Check the gas cap first.
Symptoms
- Check engine light with P0455
- Possible faint fuel smell
- Gas cap not clicking
- EVAP monitor incomplete
Causes by Likelihood
- Gas Cap Seal (Very High Likelihood): Loose or defective. Tighten until clicks. Warranty-covered if defective.
- Vent Valve Solenoid (Medium Likelihood): GM's vent solenoid. Warranty replacement.
- Purge Solenoid (Medium Likelihood): Stuck open. Warranty-covered.
- Vapor Line (Low Likelihood): Factory connection issue. Warranty-covered.
- Charcoal Canister (Low Likelihood): Rare defect. Warranty-covered.
What to Do
Tighten the gas cap and drive 2–3 days. If P0455 persists, visit a Chevy dealer for diagnostics—all free under warranty.
Warranty Coverage
Your 2023 Suburban is covered by GM's 3-year/36,000-mile warranty through 2026 and the federal emissions warranty (8yr/80k) through 2031. All EVAP repairs are free.
Safe to Drive?
Yes. P0455 doesn't affect the Suburban's engine, 10-speed, 4x4, or towing.