My 04 Silverado wont pass inspection, a emissions not ready code came up. on 2004 Chevrolet Silverado 1500

I was told it was a check engine light came on. I never had the light come on. I checked the fuse for the ECM and it was blown. After putting a new fuse in the check engine light came on, and a message REDUCED ENGINE POWER came on and the truck wouldn't go over 20 mph. I put the old fuse back in and the light and the message went away, and the truck runs fine.

Asked by for the 2004 Chevrolet Silverado 1500
you need a obd 2 code scanner to retrieve the codes