The rules for Intelligent Item Cohorts state that:
"A character with an intelligent item cohort can enhance and improve the item’s magical abilities as if possessing the appropriate item creation feat for creating an item of its type. For additional information on improving existing magic items."
Does this mean that my Character can upgrade said Item for half its normal upgrade value? Are any checks needed for this?
For the purposes of enhancing your intelligent item, pretend you have the relevant feat (such as Craft Magic Arms and Armor for an intelligent greataxe). The other crafting rules still apply.