POST UPDATED IN January, 2023The diagnostic code P0457 OBD2 indicates that a vacuum leak exists, which jeopardizes the proper functioning of the EVAP system (The evaporative emission control system). Although this code does not cause handling problems, it is necessary to make the appropriate correction as soon as possible.
Cars need two types of emission controls: active and passive. The active part is related to the control of the air-fuel ratio and the ability of the TWC (catalytic converter) to convert carbon monoxide, nitrogen oxides, and hydrocarbons into water and carbon dioxide. As for the liability that is related to this DTC code, 20% of the harmful emissions that are evaporated are represented by fuel vapors. To prevent these vapors from coming into contact with the atmosphere, they are contained within the fuel system and return to the engine through the intake manifold.
The operation of the EVAP system (Evaporative Emission Control System) is: When the engine is turned off, the venting shut-off valve and the bleed valve are closed. In this way, the fuel cannot escape to the atmosphere. At the moment the engine is started, the bleed valve opens allowing the trapped fuel vapor to be drawn into the intake manifold by the engine vacuum. At the same time, the venting shut-off valve also opens, so a small amount of air enters the carbon canister and mixes with the fuel vapor for better mixing. After it is vented and the FTP (Fuel Tank Pressure) Sensor indicates a drop, both valves proceed to close and seal the EVAP system.
