Parking Sensors - intermittent failure ??

[X5-D-Sport]

Any one know the cause of this...
Not temperature / weather or water dependant - seems random..

The sensors will flash the button in the car & an intermittent bleeping with light flashing... will not read distance, even if I get my kids to walk close to each sensor !!

or

they work perfectly of their own accord when parking or when button is pushed..

Any one got any clues as to the intermittent failure ??

Regards to all.

[DorsetBlueVinNo]

You are not alone!
Have just replaced the control unit for the pdc in my 54 3.0d and have exactly the same scenario. Great when it does work, though.
Would love anyone's input!
Still, now I've solved all my other issues, it wouldn't be any fun if everything worked perfectly!
Hope someone out there can help us.

[RoShamBo]

Checked each sensor for ticking ?
When it doesn't work / plays up - is it back AND front that doesn't work ?

Back and front sensors are on different circuits (both link to same control box) - so if both don't work then suggests the control box.
If only front or back doesn't work, suggests its an individual sensor malfunctioning.

That would be my take.

Checked the control box area in the boot for water ingress ?

[X5-D-Sport]

Control Box...

Where is it located in the boot.....  E53 2004 Diesel facelift....

Now this makes a little sense, as the boot contents & all the electric's came out a month ago to change the shocks - because the garage didn't see where the shock tops came up - so they removed every damned thing unnecessarily.... idiots ! lol

[DorsetBlueVinNo]

Lift boot floor-spare wheel out-four bolts to remove and lift the triangular frame below (with compressor dome still attached), then unbolt the plastic battery compartment cover to reveal the pdc control unit nearest you on left-should be three leads into it: white, blue & black; much easier job than it sounds-getting to it takes longer than replacing it!

[X5-D-Sport]

found the box,
All seems ok...

Just puzzling why some times it works perfectly, then not... regardless of weather or temperature.... even when stationary it works & not some times....

Can the whole system fail if just 1 sensor is faulty on the vehicle...?
as I've noticed that one of the units looks like the centre has been pushed in a few mm ...

Also, how are they removed from the rear bumper, twist & pull or some thing else ? don't want to break them off just yet lol.

Grant B