EVAP system large leak detected

What the code means

The fuel-vapor system could not establish or retain the expected sealed condition.

Severity and driving

Schedule promptly; stop for liquid fuel leakage

Plausible causes

Missing/loose fuel cap
Disconnected EVAP hose
Stuck vent valve
Larger canister or line leak

Next checks

Confirm cap installation if the vehicle uses one
Do not work around fuel vapor ignition sources
Professional smoke test if code returns

Source and boundary

Code structure follows SAE J2012. Manufacturer-specific definitions, pinpoint tests, wiring, torque, fluids, and repair procedures require authoritative information for the exact vehicle.

SAE J2012 Diagnostic Trouble Code DefinitionsReviewed 2026-08-13

Link this code to a diagnosis