engine code PO481 on 06 Jetta

Engine light came on, so we hook the scanner to it
The code was PO481 which says Cooling Fan 2 Control Circuit.

I've been noticing the car fans where idling really loud when just started

I poped the hood and only seen 1 fan running ( the right 1), are both fans post to run when start up, or does one run all the time and the other just kick in when its hot?