Hi All, after starting the engine and moving forward when accelerating slowly with the windows closed as soon as the car reaches around 20mph I hear a really faint rapid contneous clicking noise coming from the front which lasts around 1 second (you really need to concentrate to hear it). When I stop the car and move on again while the engine still running no clicking sound it only happens after the initial starting of the engine and reach around the 20mph mark, could this be linked to ABS or traction control things initialising? by the way I always turn off the eco start stop function after starting the engine. The car is 2015 XJR
Any input is greatly appreciated

 

could be your hvac system moving air around? had the blower replaced before? Not sure...

 

Air suspension pump? The pump is inhibited until the car reaches 20(ish) mph, and only runs for a few seconds, It's located at the rear of the trunk floor.

 

Even if you don't have any warning lights on your dash, I'd still check for any DTCs instead of guessing and trial and error.

As wombat suggested, normal operation of the air compressor for the rear suspension makes sense, particularly since the noise stops after a few seconds. No stored DTCs would support his conclusion.