New 2011, some codes...

Hi all, thanks for the wealth of info here, have solved many problems already just by reading this great resource!

Just got a "new" 2011, and mostly so far so good. Just took the first longer drive and got a CEL. Got myself a:

P0101 - MAF range performance problem

Will clean MAF and probe it's connections.

And:
C1242
B1803
U0100
U0155

Those ones I don't know how to address. Are those anything to be concerned about? In my sprinter there are a couple of codes that can be ignored, is there anything like that on a prius, or should those be checked into?

Thank you,
Nick