DENSO O2 LAMBDA SENSOR | FOR HONDA S2000 06-09 F20C [PRIMARY PRE-CAT SENSOR] 36531-PZX-013This Denso O2 Sensor is a replacement for Honda Part number 36531 PZX 013. This sensor is not a replacement for early type O2 sensor numbers 36531 PCX 004 or 36531 PCX 014. 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 optimal conditions.