Then pull the PCM, backprobe the connection for that circuit and check for continuity to ground.
If it is grounded then you know you have a short.
Then go back through everything you did (ie, undo the intake, and the new cooling fan, ie, remove them) and check to see where you pinched a wire somewhere. You probably pinched a harness and two wires within the harness are shorting, that is why you physically remove everything you bolted down prior, since a bolted flange somewhere is most likely where you pinched a harness, so watch carefully as you unbolt things to see where it is pinched.
Sucks, yeah, but no big deal really and the only way to fix this issue.