Kyocera FS-4000DN is showing install MK; Can the problem be fix without buying a Maintence Kit for $532?

> without buying a Maintenance Kit ?

Either you buy the kit, or you sell the printer "as is" on eBay, after buying a new printer.

You can continue to use the printer with the Install MK message showing untill one of the consumable parts fails.The consumable life is 300,000 pages and should be fitted by a technician.

You can clear the Maintenance message by scrolling down to service/Maintenance menu. I misremember which menu off the top of my head, but you should see it if you print the menu map. The 3900/4000 are keyed to total page count, not actual life of the drum unit. if the drum looks good, the developer looks good, and the fuser looks good, you can generally reset these to no ill effect. (for Kyocera, some other brands are REAL cranky about reseting mk counts.)