My PDC isn’t working. I’ve replaced the module with a second hand one which works for a second then stops.
I’ve read that a single duff sensor turns the whole system off (so listening for a ticking sound at each sensor wouldn’t then work?).
I’d rather check resistance from the PDC end of the loom.
Does anyone have a wiring diagram for the plugs that go into the PDC please?

Incidentally there’s no sign of water ingress inside the old module.

Can't really help you with a value but I'd pop them out and measure them all. If one's at fault you're most likely to find it.
I think a GAP tool can tell you which one if you have the tool.