P0456 on Your 2024 Dodge Hornet
A P0456 code on your 2024 Dodge Hornet signals the PCM has detected a very small leak (0.020-inch equivalent) in the EVAP system. Your Hornet—Dodge's sporty compact crossover based on the Stellantis STLA Medium platform shared with the Alfa Romeo Tonale—uses a modern EVAP monitoring system to verify fuel vapor containment.
Whether you have the 2.0L turbo GT or the R/T plug-in hybrid (1.3L turbo + electric motor), the gasoline EVAP system operates similarly. On a new 2024 model, P0456 is typically a minor issue easily resolved under warranty.
Likely Causes
- Gas cap not fully seated (35%) — The number-one cause on any vehicle. Ensure it clicks firmly after every fill-up.
- Software calibration sensitivity (25%) — As a relatively new model, the Hornet's PCM calibration may set EVAP thresholds that trigger codes on marginal readings. Stellantis addresses these with updates.
- Factory EVAP connection variance (18%) — Quick-connect fittings may not be 100% engaged from the assembly line.
- Purge valve or vent valve out of spec (12%) — A component slightly outside tolerance can cause borderline test results.
- New seal break-in (10%) — Fresh rubber seals and gaskets may need thermal cycling to fully seat.
What to Do
- Check the gas cap — Remove, inspect, and reinstall with a click.
- Dealer visit — Full warranty coverage means zero cost for diagnosis and repair.
- Software update — The dealer checks for TSBs and applies any pending calibrations.
- Physical repair if needed — Smoke test and component replacement under warranty.
Cost
- Under warranty: $0—covered through 2027 (basic) and 2032 (emissions)
- Gas cap (DIY first try): $15–$30
Warranty Assurance
Your 2024 Hornet is fully covered under Stellantis's 3-year/36,000-mile basic warranty through 2027 and the federal emissions warranty for 8 years/80,000 miles through 2032. Take it to the dealer—this should cost you nothing.