Viking oven display shows F04 and the oven will not start a bake or broil cycle.

Safety first: Disconnect power at the breaker. Do not force the door open if it is locked; this can damage the latch and door.

Steps to check and correct:

• Inspect door alignment: Check that the oven door closes evenly and the latch engages smoothly. If the door is sagging, adjust the hinges or tighten hinge screws.
• Access door lock assembly: On many Viking ranges, the door lock motor and switch assembly are located behind the front control panel or under the cooktop. Remove the necessary trim or top panel (with power off) to access the lock.
• Check wiring and connectors: Inspect the harness from the door lock motor to the control board for loose or damaged connectors. Reseat all plugs firmly.
• Test lock motor and switch: Use a multimeter to check continuity of the lock switch when the lock arm is in the locked and unlocked positions. If the motor does not move when a self-clean or lock cycle is commanded (with power restored briefly for testing), the motor may be defective.
• Replace faulty components: If the lock motor or switch is open or physically damaged, replace the door lock assembly as a complete unit.

When to call a technician: Door lock mechanisms are often buried behind panels and glass; if you are not comfortable disassembling the front of the range, schedule professional service.