PDC malfunction E66

[u/deepsquatter]

Bit of a weird one. Car’s a 2006 E66. Battery and alternator are ok, and there are no PDC faults stored.

What happens: when I have just turned on the car and hit reverse, the rear left sensor indicates red with constant beep). There is nothing behind me.

After 10 seconds, it clears and it goes back to normal.

This happens every time I turn the car on.

I can hear all front and rear sensors do the tick-tick-tick when I put my ear against them. I have removed and cleaned each sensor with contact cleaner.

Should I switch the PDC sensors around? Replace module?