Oven shows E4 and does not heat from the bottom in conventional modes

Safety: Disconnect power before working on the oven.

Steps:

• Remove the oven rear panel to access the lower heating element terminals (on some Bomann models the element is accessible from inside the cavity behind a cover plate).
• Check for signs of burning or discoloration at the terminals and connectors.
• Disconnect the wires and measure the element resistance. An infinite reading indicates a failed element that must be replaced.
• Inspect the wiring harness from the element to the control board for damage. Repair or replace as needed.
• If the element and wiring are intact, suspect a failed relay or track on the main control board. Board repair or replacement is usually a technician job.