Here is a synopsis of an exchange I recently had on e-mail with a fellow Honda owner. It is a good "lesson learned" and something all should check if they get and HO2 fault code...
I just installed new oxy sensor into my outboard. Has not fixed the problem. Have taken into Honda Dealer. They put their laptop on it. They cleared the o2 sensor code. Then ran my engine at idle for 2-3 minutes and the check engine light came back on and started beeping a steady beep. They put the computer back on it and sure enough the o2 sensor code had come back up.
Just thought I'd let you know I found the problem this afternoon. I decided to test the wiring loom and the loom tested all good. I had all signals, earths (grounds) and 12 volts. Upon testing the loom I found a corroded pin on the o2 sensor plug on the wiring loom side. I cut the pin off and installed a new pin and it fixed the problem. The corroded pin was the white wire with black trace which was the o2 sensor heater 12v supply.
I just installed new oxy sensor into my outboard. Has not fixed the problem. Have taken into Honda Dealer. They put their laptop on it. They cleared the o2 sensor code. Then ran my engine at idle for 2-3 minutes and the check engine light came back on and started beeping a steady beep. They put the computer back on it and sure enough the o2 sensor code had come back up.
Just thought I'd let you know I found the problem this afternoon. I decided to test the wiring loom and the loom tested all good. I had all signals, earths (grounds) and 12 volts. Upon testing the loom I found a corroded pin on the o2 sensor plug on the wiring loom side. I cut the pin off and installed a new pin and it fixed the problem. The corroded pin was the white wire with black trace which was the o2 sensor heater 12v supply.