Alarm codes in the 1000’s are external alarms. Description is the alarm was detected by the PMC ladder. If I am not mistaken these are written by the MTB. They will not be in the Fanuc manual. You will have to refer to the MTB manual or track down the alarm through the ladder or the diagnosis bits. If the MTB is still around then contact them and they will be able to tell what the alarm is from.
Are you trying to change the tool to an empty tool or the current tool in the spindle? Does this happen on every tool? Some of my older Fanucs use to be really touchy with tool changes. You couldn’t change the tool if there was a value in the offset page “wear”.