P0456 on the Redesigned 2024 GMC Canyon
A P0456 code on your 2024 GMC Canyon indicates the ECM has found a very small leak (0.020-inch equivalent) in the EVAP system. The third-generation Canyon is an all-new truck for 2023–2024, built on GM's updated midsize platform with a standard 2.7L turbocharged four-cylinder engine producing 310 hp. As a relatively new design, early-life EVAP codes like P0456 are typically minor and fully covered by warranty.
Likely Causes
- Gas cap not fully seated (33%) — The most common trigger across all vehicles. Ensure the cap clicks firmly after every fill-up.
- Software calibration sensitivity (25%) — The all-new Canyon platform may have ECM calibrations that set EVAP thresholds too sensitively. GM frequently releases updates via TSBs for new models.
- Factory connection not fully engaged (18%) — EVAP quick-connect fittings from the assembly line may not be 100% seated, creating an intermittent leak.
- Vent valve solenoid variance (12%) — A slightly out-of-spec unit can trigger marginal EVAP test results even on a new truck.
- New component break-in (7%) — Fresh seals and gaskets may need thermal cycling to fully seat.
- Purge valve irregularity (5%) — A purge solenoid that doesn't seal perfectly can cause borderline test failures.
What to Do
- Check the gas cap — Remove, inspect, and reinstall with a click. Clear the code if possible.
- Dealer visit — For a 2024 model under full warranty, this is the right approach. Zero cost for diagnosis and repair.
- Software update — The dealer checks for TSBs and applies any pending ECM calibrations.
- Physical repair if needed — Smoke test and component replacement, all covered under warranty.
Cost
- Under warranty: $0—fully covered through 2027 (basic) and 2032 (emissions)
- Gas cap (DIY first try): $12–$28
Warranty
Your 2024 Canyon carries GM's 3-year/36,000-mile bumper-to-bumper warranty through 2027, 5-year/60,000-mile powertrain through 2029, and federal emissions coverage for 8 years/80,000 miles through 2032. Take it to the dealer—this should cost nothing.