8th Gen reverse sensor issue

[psyconn]

Hey.
I have an error on my dash and its to do with the parking sensors. There is no check system message. I have looked at ways to check the sensors by listening to them but i cant hear them ticking even on the front sensors that beep if i stand in front of them. Am guessing by the symbol that the rear drivers side and rear centre sensors are either faulty or they is a dodgy wire in there causing it?
Other that taking off the rear bumper and having a look and swapping them around to test them is there another way to test the sensors??
Thanks

 

[Trawa]

Can be water ingress. Had the same issue, swapped them around to no avail, decided to just leave it and deal with it eventually. Suddenly started working about two weeks later after a dry spell and have been fine since.
HDS might be able to read the specific body control module fault but a generic OBD dongle won't tell you anything.

Rear bumper is fairly easy to take off so I would recommend taking the suspected sensors out, giving them a proper isopropyl bath and leaving them in a warm place overnight to dry as well as cleaning all the connectors with contact cleaner. If that doesn't do it, look at replacing them - about £30 a pop on eBay for legit Denso ones, just not colour matched.

 

[psyconn]

Can be water ingress. Had the same issue, swapped them around to no avail, decided to just leave it and deal with it eventually. Suddenly started working about two weeks later after a dry spell and have been fine since.
HDS might be able to read the specific body control module fault but a generic OBD dongle won't tell you anything.

Rear bumper is fairly easy to take off so I would recommend taking the suspected sensors out, giving them a proper isopropyl bath and leaving them in a warm place overnight to dry as well as cleaning all the connectors with contact cleaner. If that doesn't do it, look at replacing them - about £30 a pop on eBay for legit Denso ones, just not colour matched.

They have been like it for a long time and I just turned them off. I have only just turned them on again with the same error so decided I want to sort them. I think I will take the bumper off tomorrow weather permitting and see if I can clean them and check the wiring. Would the picture suggest its the last 2 sensors on the wiring? Could a wiring fault in the daisy chain cause this?

 

[Trawa]

Right rear and either of the middle ones.