P0440 (generic)
Evaporative Emission System Malfunction
System: Powertrain · EVAP
Severity: minor · Inspection: often fails
Description
EVAP system leak detected. First step: check that the gas cap is tight and not damaged. Then inspect EVAP hoses, purge valve, and canister vent.
Diagnostic snapshot P0440
- Difficulty
- 6/10 — Intermediate diagnostics
- Est. repair cost
- $120 – $450 (parts + typical shop labor)
Diagnostic workflow
- Confirm P0440 with a live scan — note pending vs stored and freeze frame data.
- Inspect wiring/connectors and related sensors before replacing modules.
- Clear codes and road-test; re-scan after two drive cycles if the monitor must set.
Topics
- OBD-II and scan tools (guide)
- Powertrain DTCs (P-prefix) (system)
Related symptoms
None linked yet.
Common fixes (curated)
None linked yet.
Related articles
- Check Engine Light P0440 After Gas Cap 2017 Toyota Prius V
- Check Engine Light: 2019 Toyota Paseo General EVAP System Leak
- Gas cap not sealing, check engine light 2019 Toyota Prius
- Check Engine Light On for General EVAP System Leak 2018 Toyota Prius
- Check Engine Light On: Loose Gas Cap on 1998 Toyota Supra
- Gas Cap Not Sealing, Check Engine Light 2001 Toyota Corolla
- Check Engine Light P0440 General EVAP Fault 1998 Ford Crown Victoria
- Check Engine Light On for General EVAP Leak 1999 Ford Expedition
- P0440 1996 Ford Taurus: EVAP System Malfunction Guide
- P0440 2002 Toyota Avalon: EVAP System Diagnostic Guide
Diagnostic bundle (JSON)
Machine-readable graph: related codes, symptoms, fixes, topics, articles, and curated sources rows. Append &external=1 for optional YouTube / Google CSE hits when API keys are configured (see web/.env.example).