Hey guys..i got a P0492 code today,after scanning it, it comes up with Secondary Air injection system..After reading i have a idea about whats the problem,but not too sure..but looking around in the engine area,i noticed a huge rip in a hose,and figured this rubber tube to be the problem..can you pinpoint this hose? and tell me what its for..the tear in the hose in the pic ,is where the black circle is..thanks guys btw..its a 2001 4.2l

if you double click the pic,it goes full size

 

That pic is pretty bad to see anything .. but from what you are explaining and the general location of where you took the picture I'd sat it is the SAI hose from the pump to the rear of your engine. Mine was also completely ripped and I replaced with a heater hose from Autozone for about 10 bucks. You could go to Audi and get that hose for about 100$ too if you really wanted
Simple fix: get 2 clamps with a screw for the new hose; remove the old clamps with pliers; attach new hose; fasten the clamps and you are ready to go.