Tracking P0440 on Your 2020 Nissan Frontier
A P0440 code on your 2020 Nissan Frontier opens a case into the EVAP system. The 2020 Frontier, the final year of the second generation, uses the venerable 3.8L V6 engine. This long-running platform has well-known EVAP characteristics, and the failure points are thoroughly documented.
Symptoms
- Check engine light on
- Faint fuel odor near the truck
- Slight MPG decrease
- Fueling difficulties
- Emissions test failure
Your Frontier drives and tows normally. P0440 does not affect the V6 or automatic transmission.
Ranked Causes
- Gas Cap — Worn after years of use. Estimated repair: $5–$20.
- Purge Volume Control Valve — Known Nissan failure on the VQ/VR series engines. Estimated repair: $75–$195.
- Canister Vent Control Valve — Located near the charcoal canister at the rear. Estimated repair: $85–$210.
- EVAP Leak Detection Pump — Nissan's self-test pump degrades over time. Estimated repair: $135–$330.
- Deteriorated EVAP Hoses — The long-running Frontier design has hoses exposed to years of road debris and heat. Estimated repair: $35–$120.
Diagnosis
- Replace gas cap and clear code
- Scan for all EVAP codes
- Test PVCV and vent control valve
- Check leak detection pump
- Smoke test and hose inspection
Costs
- Gas cap: $5–$20
- PVCV: $75–$195
- Vent control valve: $85–$210
- Leak detection pump: $135–$330
- Hoses: $35–$120
- Diagnostic: $80–$150
Safe to Drive?
Yes. No impact on towing, off-road capability, or any drivetrain component.
DIY Friendly
The Frontier is very DIY-friendly with a spacious engine bay and good access to most EVAP components. The second-gen Frontier has a large enthusiast community with detailed repair guides.