I have a just out of warrantee RR TD6 which has a fault with the sensors.

When turning the sensors on, whether by selecting reverse or using the button, I hear a long solid tone from the rear sensor followed by the activation light on the switch flashing.

It done this for a couple of days then sorted itself. Now it's failed again.

Does anybody know what's going on apart from possible failed sensor/s.

I've cleaned the faces of the sensors.

It could be one of the sensors going. I had a problem on my old BMW 330 coupe which I'd guess used the same sensors due to BMW's involvement in the TD6/L332 development.

AFAIK if you can hear the sensors ticking when reverse is selected (obviously without the engine running!) then it is doing its job. Any sensor thats silent or ticking less/quieter than the others will be the faulty one. Then can also play up when they are wet too.

My BMW fault was intermitent and I never got to the bottom of the problem but reverse parking wasn't such a problem with that car though

Did you find the problem with your sensors, I have the same problem??

Ended up putting it into Land Rover and they renewed the sensor.