This forum is great! I wish I'd found it 4 yrs. ago when I bought my 2001 Discovery (103,500 miles).
Here's what's going on with it: every time I start it and intermittently while driving, I hear a whirring sound from the
pass. firewall ( is it the secondary air pump?). The SES light
came on recently, I had it checked and the codes were P1414
and P1417-secondary air system faults. The tech cleared them for me and they haven't come back on- I've driven about 20 miles since resetting. What do I do next?

 

Wait and see.
Could have been water in the system or the beginning os a failure.

 

from what I have seen on here, you whirring is the pump coming on. Like Mike said, wait it out and see if anything comes back..

 

Thanks, I'll keep watching it.