Hey, I pulled a CEL code number 65 - Rear O2 Sensor Circuit Malfunction for a 5th gen prelude. Does that mean I have to replace the rear O2 sensor to fix the problem. Or does the problem lie somewhere in the circuit. Thanks for any replies.

yes. replace it. back in business

Ok. Thanks. I might have to do that next week. But you think its ok to delete the code for now until I replace the O2 Sensor?

it wont make any difference. if you delete the code, your car will throw it again if the problem isnt fixed. thats what happened to me.

I am throwing the same code but I believe it started when I put on an aftermarket exhaust, would changing the o2 solve the problem? also can u lose hp from a bad o2 sensor?