Out of the blue came this dashboard display "bootlid open" which blocked the gear leaver in P position. What causes this false signal?

 

Scan vehicle for fault codes and post them here.

Possible worn brake pedal switch but scan first.

 

To clarify, the original poster appears according to their profile to have a 2000 XJ8 which makes it a X308 model.

I would suggest you repost in the x308 forum to access members that have the same model car as yours.
It is a good idea to include in your signature your model, year of production, mileage, engine and trans, so anyone looking at your posts can quickly understand what you have and offer help faster.

But on the face of it I would expect you have a boot interlock switch that is giving a false reading, the x350 (2003 and later) has the Boot lid switch integrated in the boot latch assembly, not sure about the X308.

Can you still access the boot?
If you put your phone on video record mode and then put your phone in the boot while closing the lid, does the phone record the boot light going out when you review the video?
If light goes out when boot is closed, then boot switch likely operating properly which may mean you are looking elsewhere for the actual cause.

 

My boot open light comes on fairly often. Either I press the button on my fob and don't catch it or one of my grand kids will
press the trunk's button when getting into the car. It has never caused a problem with driving the car. Since the lid is pretty heavy I don't always pull over and shut the trunk immediately. I know I have driven to the nearest stop sign a block away and the lid stays down just fine and I had full freedom to shift and drive. Is the actual trunk lid functional as far as opening and latching when shut? Perhaps you have a problem in the J-gate or somewhere else in the console? Good luck.

 

will do so, thank you very much

 

thank you Mark

 

yes th boot still opens with the key.( i dont have a remote activator)