My front parking sensors have stopped working. Originally this caused the front and rear sensors to fail, so whenever I engaged reverse gear, a loud long beep would happen and the sensor button would flash and then I would have no sensors all round.

I hooked the car up to elmconfig and completely disabled the front sensors so that the car thinks it only has rear sensors. This made the rear sensors start working as normal again.

I now need to suss out what is causing the front sensors to fail. Could a wire have come loose somewhere or broken? I have pulled each sensor out and all appear to be fine and connected properly.

 

Any help?

the 4 sensors are on a harness that runs from right to left as you stand looking at the front of the car, just under the OS headhamp you will see the connector block, check that to make sure its ok, no water ingress or anything. the wires  are all clipped on to the bumper with little metal clips, might be worth inspecting those as well, a multi meter would be handy to identify any shorts