# P0440 — Evaporative Emission System Malfunction

> ClearTheCode diagnostic code reference (not OEM service data).

Source: https://clearthecode.com/codes/P0440

**System:** Powertrain · EVAP

**Severity:** minor

## 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

- **Difficulty:** 6/10 — Intermediate diagnostics
- **Est. repair cost:** $120 – $450

## Diagnostic workflow

1. Confirm P0440 with a live scan — note pending vs stored and freeze frame data.
2. Inspect wiring/connectors and related sensors before replacing modules.
3. Clear codes and road-test; re-scan after two drive cycles if the monitor must set.

## Related articles

- [Check Engine Light P0440 After Gas Cap 2017 Toyota Prius V](https://clearthecode.com/articles/check-engine-light-p0440-after-gas-cap-toyota-prius-v-2017)
- [Check Engine Light: 2019 Toyota Paseo General EVAP System Leak](https://clearthecode.com/articles/check-engine-light-evap-leak-general-toyota-paseo-2019)
- [Gas cap not sealing, check engine light 2019 Toyota Prius](https://clearthecode.com/articles/gas-cap-not-sealing-check-engine-toyota-prius-2019)
- [Check Engine Light On for General EVAP System Leak 2018 Toyota Prius](https://clearthecode.com/articles/check-engine-light-evap-leak-general-toyota-prius-2018)
- [Check Engine Light On: Loose Gas Cap on 1998 Toyota Supra](https://clearthecode.com/articles/check-engine-light-gas-cap-loose-toyota-supra-1998)
- [Gas Cap Not Sealing, Check Engine Light 2001 Toyota Corolla](https://clearthecode.com/articles/gas-cap-not-sealing-check-engine-toyota-corolla-2001)
- [Check Engine Light P0440 General EVAP Fault 1998 Ford Crown Victoria](https://clearthecode.com/articles/check-engine-light-p0440-evap-fault-ford-crown-victoria-1998)
- [Check Engine Light On for General EVAP Leak 1999 Ford Expedition](https://clearthecode.com/articles/check-engine-light-evap-leak-general-ford-expedition-1999)
- [P0440 1996 Ford Taurus: EVAP System Malfunction Guide](https://clearthecode.com/articles/p0440-ford-taurus-1996-diagnostic-guide)
- [P0440 2002 Toyota Avalon: EVAP System Diagnostic Guide](https://clearthecode.com/articles/p0440-toyota-avalon-2002-diagnostic-guide)