I have checked again today with the car on an horizontal surface, engine at température and the car stopped. It worked and give an indication.
Almost all electronic sensor (non dipstick) types will not give a reading with the engine running as so much of the oil is in circulation that you would get a fault of low sump level
Remember 'normal' engines with dipsticks need you to leave the oil to have drained into the sump to get a correct reading, on level ground too
