System: Emissions Control · Standard: SAE J2012 generic code · Severity: Low urgency
No immediate safety risk. Monitor it and fix it at the next service, but do not ignore it indefinitely.
A large leak is usually visible. Check the fuel cap first, then look for a hose hanging loose.
Start by reading every stored and pending code, not just this one. A single fault frequently sets three or four codes at once, and the first one in the freeze-frame data is usually the cause while the rest are consequences.
The evap system has a large enough leak that it cannot build pressure at all. Evaporative Emission Control System Leak Detected (Large Leak) is a generic emissions control code defined by SAE J2012, so it carries the same meaning on every OBD-II vehicle.
Low urgency. No immediate safety risk. Monitor it and fix it at the next service, but do not ignore it indefinitely.
In rough order of how often they turn out to be the problem: Fuel cap left off or badly seated; Disconnected evap hose; Failed purge valve stuck open.
P0401 Exhaust Gas Recirculation Flow InsufficientP0402 Exhaust Gas Recirculation Flow ExcessiveP0411 Secondary Air Injection System Incorrect FlowP0420 Catalyst System Efficiency Below Threshold (Bank 1)P0430 Catalyst System Efficiency Below Threshold (Bank 2)P0440 Evaporative Emission Control System MalfunctionCode number, system and definition follow the SAE J2012 / ISO 15031-6 generic diagnostic trouble code standard. Symptoms, causes and severity are the standard generic diagnostic logic for that fault. This page does not contain manufacturer-specific procedures, part numbers or pricing.