I have a 2000 Honda Civic EX coupe and it is pulling a code 65. I know it has two O2 sensors. I can see one sticking out right just below the oil filter. Is that the primary or secondary? Where are the primary and secondary oxygen sensors located on the car? Thanks in advance.

 

primary is pre-catalytic converter, secondary is post.

 

on cat conveter,

 

Yep, you see the primary O2 sensor near the oil filter. The secondary is plugged into the top of the cat.

Did you already check whether fuse 15 is blown?

 

Thanks for the replies. Hmm I didn't know there was a 15 fuse for the O2 sensor. I will check that out. Thanks.