What does code P0456 mean?

Q: What does code P0456 mean?

Evaporative Emission System Leak Detected (very small leak). P0456 means the powertrain control module (PCM) has detected a very small leak in the evaporative emission (EVAP) system, typically equivalent to a hole smaller than 0.02 inches. The computer runs a self-test that pressurizes or pulls a vacuum on the fuel tank and vapor lines, then measures how quickly pressure or vacuum bleeds off; a slow loss triggers this code.

DTC codes / P04xx · Auxiliary emission controls / P0456

P0456Evaporative Emission System Leak Detected (very small leak)

P0456 means the powertrain control module (PCM) has detected a very small leak in the evaporative emission (EVAP) system, typically equivalent to a hole smaller than 0.02 inches. The computer runs a self-test that pressurizes or pulls a vacuum on the fuel tank and vapor lines, then measures how quickly pressure or vacuum bleeds off; a slow loss triggers this code.

SystemPowertrain

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaAuxiliary emission controls

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.