[eschaider]

You can shut off the rear sensors and the engine will run OK, Sunman. However, you can not shut off the fronts. I am unfamiliar with the Australian emissions requirements but I would bet the fronts are absolutely necessary. I am not certain about the rears. They might be also.

While I could be incorrect, I was under the impression the OP was speaking about the fronts but, again, I could be wrong.

Your, observations about Ford using the same sensor in many vehicles is consistent with my understanding also. Which is why I am surprised that Ford would not have sensors at a dealership to replace failed components in customer vehicles.