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. * For inspection and repair of the EFI system, refer to EFI Section.