SYSTEM PURPOSE System | Abbreviation | Purpose Positive crankcase ventilation | PCV | Reduces blow-by gas (HC) Fuel evaporative emission control | EVAP | Reduces evaporative HC Dash pot | DP | Reduces HC and CO Exhaust gas recirculation | EGR | Reduces NOx Three-way catalyst | TWC | Reduces HC, CO and NOx Electronic fuel injection* | EFI | Regulates all engine conditions for reduction of exhaust emissions Remarks *For inspection and repair of the EFI system, refer to EFI section.