Had unexpected voltages on relay board pins and no change when cycled from lower to upper element heating in pre-heat cycle. Changed out Relay and Power Board. This resolved odd voltage readings, but then was just 0 volts and upper oven still wouldn't heat. Ended up also having to reset Thermal Circuit Breaker oven has. (There were videos on YouTube showing how to do.) This combination of actions resolved the problem. Don't plan on using self-clean again.