Using AI help, we determined that the Bosch oven has an upper and lower heating element. Both are used for preheating, but the lower element keeps the oven at the set temperature. Since the oven wasn’t keeping temperature it was likely a burned out lower heating element. We turned off the power to the unit, removed the door and removed the oven from the wall. We disassembled the lower part of the oven and replaced the heating element we bought from AppliancePartsPros.com. They shipped same day and I received it in 2 days. It is an OEM part, which is what I wanted. Reassembled and reinstalled and now works great.