Question about Secondary Air Pump

[tony77ca]

I have a 2002 BMW X5 3.0 with 65K miles on it. A few days ago, SEG light came on, I checked it with OBD II and it gave me codes P0491 and P0492.

After doing some research on this site, I found that these are due to the failure of the Secondary air pump and the valve. In the threads that I have read, it was mentioned that the valve should be changed first and if the problem is not resloved then the pump should be changed beause it is more expensive.

My question is will the pump work at all if it needs changing?

I noticed that when I start the car on a warm day that the pump will be turned on for around 30 seconds with a very loud noise. Is this supposed to be normal? Would it make any noise or work it is not working and needs changing?

Thank you very much, your help is greatly appreciated.