Good evening!

We have a 2005 vintage KitchenAid Superba KEBC208KBT03 double oven. After a power failure, it beeped a minute or so after power came back on and displayed "F5 E1".

Hitting UPPER OVEN CANCEL clears that, but it comes back in 30 seconds or so. LOWER OVEN CANCEL doesn't do anything.

Both doors open, and the lights light when the doors open and the lights go off when the doors close. Both latches articulate and make the lights go on. Both doors seal properly.

If we clear the code with UPPER OVEN CANCEL the upper oven runs just fine. The lower oven kicks in to a heating cycle, but after 30 seconds or so it kicks off and the error code display turns back on.

I tripped the breaker for 15 seconds and cycled power. The oven came on, and 30 seconds later the error came back on with some beeps.

I tried cutting power for a minute, ten minutes, an hour, and 24 hours. Restoration of power results in the same thing each time without variation. Display comes back, and 30 seconds later we get F5 E1.

No combination of reset keystrokes I found online seems to have effect.

I found a keystroke combination that's supposed to kick the oven into a diagnostic mode, but that doesn't seem to have any effect.

Do I need a "latch controller sister card", or are there more diagnostics I can go through?

Thanks!