It should behave just like your other AF-S lenses.
Obvious bits first: is the M / M/A switch on the lens set to M/A, and have you got the focus mode selector on the camera set to S or C?
Slightly less obvious bits: have you got the focus limit switch on the lens set to 'full'? If it's set to '2.5m to infinity' then the lens won't focus on anything closer than 2.5m. Are you inadvertently pressing one of the focus lock buttons (the three circular buttons about half way down the lens barrel)? They stop the autofocus when you press them.
If it's none of the above - and your other AF-S lenses still work OK - then I'd guess you've got a faulty lens.