2009 parking sensor problem

[liamers]

When I turn the key to the point the dash lights up and put it in reverse, the parking sensors work correctly if there's something close behind me.

But if I have the ignition on and put the car in reverse initially a loud long beep will sound and then a reversing beeping sound similar to how large vehicles have starts. This beeping is audibly different in tone to the sensor beeps. The beeps then stop after a couple of seconds but if I continue to reverse and approach something close to my rear the parking sensors do not engage at all.

If I turn off the car then turn the key to the dash light again and put it in reverse the parking sensors will immediately start beeping to let me know I'm very close to something.

Anyone know what is causing this weird malfunction? The reverse beeps seem to cut off the parking sensor beeps and don't work while the ignition is running

 

[novocaine]

are they factory fitted or aftermarket?
I'd assume aftermarket as I don't think they came with them from Nissan at the time. could be wrong though.
if aftermarket they will be connected to the reversing light, so a quick dig in the boot for the control module will be a good first start. once found, post a picture so we know what we are dealing with, then we can figure out a solution (which maybe replacing them with new to be honest as it sounds like the control module has died or you have a faulty sensor)