General Information

Engine Control
P0456 Evaporative Emission System-Leak detected (very small leak) - General Information

General Description

The evaporative emission control system prevents hydrocarbon (HC) vapors from the fuel system from escaping into the atmosphere where they could form photochemical smog. Gasoline vapors are collected in the charcoal canister. Periodically the ECM checks the system for vacuum decay, valve leakage and restrictions. The ECM will close off the CCV and then momentarly open the PCSV to lock vacuum in the system. Then the ECM monitors the FTPS signal to check the pressure change.

DTC Description

Checking output signals from fuel tank pressure sensor under evap.system test, if fuel tank's vacuum decay slope is higher than prescribed threshold, ECM sets P0456 and then MIL(Malfunction Indication Lamp) turns on.

DTC Detecting Condition