EVAP system codes (P044x–P045x)
The fuel-vapor system has a leak — often as simple as a loose or worn gas cap, sometimes a hose or valve.
Important: Content here is general information only, not professional mechanical advice or a diagnosis for a specific vehicle. When in doubt, have a qualified mechanic assess it promptly.
- P0455: Evaporative Emission Control System Leak Detected (Gross Leak) — The evaporative emissions (EVAP) system, which traps fuel vapors from the tank instead of venting them, has a large leak — the system cannot hold pressure during its self-test.
- P0442: Evaporative Emission Control System Leak Detected (Small Leak) — The EVAP system, which traps fuel vapors instead of venting them, has a small leak — it cannot quite hold pressure during its self-test.