P0455 Evaporative Emission Control System Leak Detected (Gross Leak/No Flow)

P0455 indicates a large evaporative-emissions leak or no-flow condition. It is an EVAP-system leak-detection lead, not a direct part diagnosis.

Code status

Needs verification

Not yet verified against SAE J2012_202509 / J2012DA. Treat unverified rows as a lookup aid, not repair authority.

System
Emissions
Scope
iso-sae-controlled-p0
Standard
SAE J2012 / ISO 15031-6
Source
legacy-import

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not assume the gas cap is always the fault; a large leak can come from valves, hoses, seals, or damaged EVAP plumbing.

Useful checks before replacing parts

Related OBD-II codes

These nearby emissions entries can help compare wording and fault area. They may share the same verification status as the source database.