DENSO O2 LAMBDA SENSOR | FOR HONDA S2000 AP1 01-06 F20C [PRIMARY PRE-CAT SENSOR]This Denso O2 Sensor is a replacement for Honda Part numbers 36531 PCX 004 or 36531 PCX 014. This sensor is not a replacement for 36531 PZX 013 which is found on later specification vehicles. The air fuel mixture in an engines combustion chamber can affect how hot, how quickly and how cleanly the fuel burns. For optimum combustion, the air to fuel ratio needs to be within a certain window. For specific driving conditions, the engine may run in sub