P0455 Investigation on Your 2024 GMC Sierra
A P0455 on your 2024 Sierra means the ECM detected a large EVAP leak. Whether you have the 2.7L turbo, 5.3L V8, or 6.2L V8, your Sierra is fully under warranty. Gas cap first.
Symptoms
- Check engine light with P0455
- May also see P0449 (vent valve circuit)
- Possible fuel smell
- Gas cap not seating
Top Causes
- Gas Cap Seal (Very High Likelihood): Loose or factory defect. Warranty-covered.
- Vent Valve Solenoid (Medium Likelihood): GM's EVAP vent valve—a known GM weak point. Warranty-covered.
- Purge Solenoid (Medium Likelihood): Stuck open. Warranty-covered.
- Vapor Line (Low Likelihood): Assembly issue. Warranty-covered.
- ECM Software (Low Likelihood): Calibration update. Warranty-covered.
GM EVAP Note
GM trucks often set P0449 alongside P0455. P0449 points to the vent valve solenoid circuit. If both codes are present, the vent valve solenoid is the likely culprit. GM dealers use GDS for EVAP diagnostics.
Warranty
Your 2024 Sierra is covered by GM's 3-year/36,000-mile warranty through 2027. Federal emissions (8yr/80k) extends through 2032.
Safe to Drive?
Yes. P0455 doesn't affect any engine, 4WD, towing, or MultiPro tailgate.