Kia Troubleshooting Questions? Ask a Mechanic
It sounds like the programming for the keys needs to be redone. It sounds like you have access to a programmer?
If you want to try to reset the computer and see it it will start a few more times in the meantime you can force a reboot:
Remove both battery cables and touch them together for about 2 minutes. This will draw down all the voltage in the computer and force it to reboot.
Reconnect the battery like normal and see if it will start.
The security system on the sedona is a starter kill system. That means if the key code doesn't match it won't crank. It's not the style that cuts the fuel pump but lets you crank.
None of the keys work?
Have you checked for voltage at the starter? You should get 12 volts at the large red starter wire and 12 volts on the smaller trigger wire with the key in the crank position.