My check engine light came on recently. I took it to autozone and was told I need a new o2 sensor. Can anyone tell me exactly where it is located? (diagram would be helpful) Is this a diy job?

 

Well, it would help if you could give the the year.

To my knowledge there are 3 o2 sensors. intake header and exhaust.

 

the same here... its probably the top one, if the code was P 1165 its top so its located on the front or side of the mid-upper part of the header. all you need is a 7/8" wrench to take it off i believe. but for now you can unhook your battery for about 5-10 min to reset the ecm and the light will go off and come back on in about 3-4 days or so

 

My bad, its a 98 civic lx and I was told it was the primary o2 sensor.

 

i only have 2, one on my header, and one after hiflow cat. converter

which btw the top o2 sensor is b4 the cat converter