P0456 on Your 2020 Maxima: Investigating the Micro-Leak
Your 2020 Maxima (8th generation, A36) has triggered P0456—a very small EVAP leak at 0.020 inches. The flagship sedan's 3.5L VQ35DE V6 producing 300 hp uses Nissan's EVAP system with the unique leak detection pump. At 5–6 years old, component aging is the primary concern.
Clues
- Check engine light on
- P0456 stored
- No performance symptoms—all 300 hp present
- CVT works normally
- Gas cap may show wear
Suspects
- Gas Cap Seal (High Likelihood): Five years of wear. $10–$15.
- EVAP Leak Detection Pump (High Likelihood): Nissan's unique component. Known failure. $180–$320.
- Purge Volume Control Valve (Medium Likelihood): VQ35 heat over time. $120–$240.
- Canister Close Valve (Medium Likelihood): Age-related. $130–$250.
- EVAP Hose Micro-Crack (Low Likelihood): Rubber aging. $100–$220.
Diagnostic Steps
- Replace gas cap ($10–$15)
- Clear code and drive 50+ miles
- Test leak detection pump with CONSULT if code returns
- Check PVCV and canister close valve
- Smoke test for persistent leaks
Costs
- Gas cap: $10–$15
- Leak detection pump: $180–$320
- PVCV: $120–$240
- Canister close valve: $130–$250
Can I Drive?
Yes. P0456 has zero impact on the Maxima's 300-hp V6, CVT, or any performance feature.
Warranty
Nissan's 3yr/36k expired around 2023. Federal emissions (8yr/80k) covers EVAP through 2028. VQ35 EVAP parts are shared with Altima, Pathfinder, and Murano—widely available.