Investigating P0456 on Your 2020 Camaro
Your 2020 Camaro (6th generation) has triggered P0456—a very small EVAP leak at 0.020 inches. Whether you have the 2.0L turbo, 3.6L V6, 6.2L LT1 V8 (SS), or the supercharged 6.2L LT4 (ZL1), GM's EVAP system is shared across all powertrains with a traditional threaded gas cap.
Clues
- Check engine light on
- P0456 stored in ECM
- No performance changes
- Track readiness unaffected
- Gas cap may be slightly loose
Suspects
- Gas Cap Seal (High Likelihood): Worn after 5+ years. Replace for $10–$15.
- Vent Valve Solenoid (High Likelihood): GM's primary EVAP failure point. $80–$220.
- Purge Solenoid (Medium Likelihood): V8 heat is significant on performance cars. The LT1 and LT4 run particularly hot. $80–$220.
- EVAP Hose Micro-Crack (Medium Likelihood): Exhaust heat from the V8 affects nearby lines. $100–$250.
- Charcoal Canister (Low Likelihood): High-RPM use and fuel slosh can stress the canister. $200–$400.
Diagnostic Steps
- Replace gas cap ($10–$15)
- Clear code and complete a drive cycle
- Inspect vent valve solenoid if code returns
- Smoke test for persistent micro-leaks
- Check for P0449 companion code
Costs
- Gas cap: $10–$15
- Vent valve solenoid: $80–$220
- Purge solenoid: $80–$220
- EVAP hose: $100–$250
- Charcoal canister: $200–$400
Can I Drive Hard?
Yes. P0456 has absolutely no effect on the Camaro's performance, horsepower, track capability, or any mechanical system. SS, ZL1, 1LE—all perform identically with this code present.
Warranty and DIY
GM's 3yr/36k expired around 2023. Federal emissions (8yr/80k) covers EVAP through 2028. Gas cap is instant. Vent valve solenoid is accessible with basic tools. Performance car owners often prefer DIY for simple repairs like this.