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O2 sensor is a feedback sensor to correct the A/F ratio.at idle and low rpm it is more important to correct the A/F ratio so combustion will be perfect at WOT need more fuel so that time O2 sensor signals just ignore and work on the more power that's why buzzer will go off at WOT that time ECU supply max fuel ratio . so when sensor is fail ECM cant get correct feedback, it will supply max fuel at idle and low rpm also.engine will run with rich mixture A/F ratio, will have bad exhaust rough idle more fuel consumption.
After so many modification this sensor continue to fail so who has too old engines(out of 5 year warranty) they don't like to pay so much of money on this. for this if somebody wants cancel this sensor and get away from nonstop buzzer,Honda has a replacement kit that will cancel the O2 sensor. it include new ECU,and adapter for sensor port. But we haven't seen it yet.
wajira