Silvaire, yes, correct but I disagree about the effects of disconnecting (or a failure of) the O2 sensor.
I once went for a test drive in a BMW, with a view to buying it from the garage. It was immediately noticeable that there was something not right about the performance of the car, despite there being no OBD fault code showing. The effect was a "surging" sensation, then a hesitation under acceleration. I agreed to buy the car but insisted that the garage would be responsible for fixing the problem. They agreed, but all they kept doing was checking the fault codes and they were stumped. I suggested they should change the O2 sensor but they couldn't see that this would make any difference. To cut a long story short I eventually bought a new sensor myself, took it to them and asked them to change it, or the car would go back to them under the Sale of Goods act. I also said that if it cured the fault I would expect them to reimburse me for the new sensor. They agreed but were very sceptical. They fitted the new sensor, the car's performance was immediately transformed and they reimbursed me. The old sensor was probably still putting out a very weak voltage so the OBD didn't pick it up as a fault.
However, we were originally discussing "mechanical" aircraft fuel systems designed and built almost forty years ago.
