Are they the same? I know the d-series is a 4 wire.

 

Anyone?

 

It should work. I ran 98 GSR primary and secondary o2 sensors on my 96 ex for smog and I passed emissions fine (keep in mind I live in the state of smog ****'s).

 

Looking up the 99 EX primary O2 sensor the part number is 36531-P2P-A01 (Honda Code 600020). That O2 sensor only cross refrences to 99 and 00 Civic EX 2 and 4dr models only. The Civic Si primary O2 sensor part number is 36531-P2T-003 (Honda code 601826) and that fits the 99-00 Civic Si. I wouldn't recommend using the D-series O2 sensor because im pretty sure there is a big enough difference between the D-series O2 sensor and the Si O2 sensor that you may have a problem if you try to use a D-series O2 sensor. Hope this helps.

 

Only real difference between the two part numbers are the wires on the two o2 sensors. Otherwise they are interchangable