The P0440 Case File: Your 2020 Nissan Maxima
A P0440 code on your 2020 Nissan Maxima sends us investigating the EVAP system. The Maxima's 3.5L VQ35DE V6, Nissan's flagship sedan engine, uses a well-established EVAP setup. After several years of service, certain components are prime suspects. Let's examine the evidence.
Symptoms
- Check engine light on
- Faint fuel odor
- Slight fuel economy decrease
- Fueling difficulties
- Emissions test failure
Your Maxima's 300-horsepower V6 and CVT are completely unaffected. Performance, handling, and comfort remain unchanged.
Ranked Causes
- Gas Cap — Worn gasket after years of use. Estimated repair: $5–$20.
- Purge Volume Control Valve — The PVCV on the VQ35 is a well-known Nissan failure point. Estimated repair: $80–$210.
- Canister Vent Control Valve — Located near the charcoal canister. Estimated repair: $90–$225.
- EVAP Leak Detection Pump — Nissan's self-test pump. Estimated repair: $150–$350.
- Vapor Hose Deterioration — Age-related cracking. Estimated repair: $40–$130.
Diagnosis
- Replace gas cap and clear code
- Scan for all EVAP codes
- Test PVCV and vent control valve
- Verify leak detection pump function
- Smoke test for leaks
Costs
- Gas cap: $5–$20
- PVCV: $80–$210
- Vent control valve: $90–$225
- Leak detection pump: $150–$350
- Vapor hoses: $40–$130
- Diagnostic: $80–$150
Performance Impact
Zero. All 300 horsepower are still available. P0440 does not affect engine output, CVT behavior, or sport mode operation.
DIY Feasibility
Gas cap is easy. The PVCV on the VQ35 is accessible in the engine bay. Rear components require lifting the vehicle. Moderate DIY difficulty overall. The Maxima shares many components with other VQ-powered Nissans, so parts and guides are widely available.