I'd start by doing a 'Cold Boot' of the entire system. That's the remove the battery cables, touch them together, sing a happy song, drink a beer and re-connect. This will force all the computers to completely re-boot and re-establish a friendly (hopefully) communications relationship with each other.....and it will clear the codes.
I just have this feeling that it's either a computer mixup, or the driver (the electronic version that operates electricity, not the biological form that operates the steering wheel
) that operates that light is internally shorted out....which would require replacement of the instrument cluster. Although possible (high improbable) this is caused by an external module sending data to turn the light on, I'm reluctant to believe that, as the same signal that turns it on, tells the truck to NOT start as the key is the wrong key.