I am in dire need here....I am getting a cel 1 and cant get it to go away.. I have tried a 2 different o2 sensors one out of a working car and a brand new one...It is a 4 wire o2 sensor.. My motor 94 b16a sir II. The car 95 honda civic lx. using p30 ecu mt obd1. I cant figure it out to save my live PLEASE HELP.. I hope I gave you enough info...

code 1
Oxygen sensor or circuit.

 

did you follow the o2 sensor wiring to make sure it isnt cut or pulled out of any connections?

 

Allof t hem are good....I took a meter to them.. and looked at every one of them..

 

check the cat to see if that's clogged.

 

crack open the ECU and see if there is any mold or gunk build up... it might be "leaking"

 

Are all the grounds intact? 1 wire O2 sensors ground right to the exhaust, I'm not sure if 4 wires do the same.. I would swap ECUs just to make sure that isn't the problem. Don't want to bang your head into the wall and find out it's not the O2 after all..