Hi all posting as it may he!p others
03 l 322 vogue
My parking sensors wernt working when I bought 9 months ago. My tool said rear centre right. Took the plunge and bought a sensor and removed the rear bumper . Popped the sensor out and fitted the new one ,even colour sprayed it first. Been caught before so I engaged reverse still long bleep. Attached the tool and same fault. So I swapped the outer sensor for the supposed faulty one . Tried the old sensor on the working one position and it came back good ,so I have a wiring problem . I cut off the insulation tape and couldn't find any obvious breaks. Now the sensors have three wires so I carefully pulled each of them from the connector to the loom. Two were fine but low and behold the green wire pulled out.I followed the cable and found the break . With the actual internal wire being green rotted it looks as if someone had used one of those prob wires and not resealed the punch wire with glue. I soldered the wires together covered with heat shrink and 're tapped the loom . Checked in reverse and now the sensors rear and front work. Received the bumper making sure no wire trapping was obvious .
Hope this may help another poor ole soul ,lol
Thanks guys

Good, patient diagnostics! Thanks for sharing. TDV8 4.4 2012