2000 grand am high idle

My daughter's 2000 grand am is idling at about 1800 rpm's. It has the v-6 with auto trans. She told me her check engine light came on over the weekend while I was out of town, so she took it to a parts house to pull the code. They were unable to pull the codes because they said a fuse must be blown. I have'nt had a chance to look at it yet so any help beforehand would be great.

idle air control valve could be stuck or not working try cleaning it.

don't have e-diagram handy to see why they couldn't read codes but most likely for some reason their scanner couldn't communicate with your pcm. On some pontiac models if fuse for cigarette lighter is blown then obd2 connector will not work and thus information to scanner can't be sent. So in the meantime check that fuse and try to go to auto zone again for codes.