Oven shows E4 and will not start a cooking program, or stops mid-cycle with a beeping alarm.

Safety first: Disconnect the oven from power before adjusting the door or accessing the lock mechanism.

• Check door closure: Ensure the door closes fully and evenly. Look for bent hinges, warped door, or obstructions on the gasket.
• Inspect latch and strike: Examine the metal latch hook on the door and the strike on the oven frame. Tighten loose screws and gently realign if the latch does not engage smoothly.
• Test door switch: On models with a visible plunger switch, press it by hand and listen for a click. If no click or if the oven light does not respond, the switch may be faulty.
• Check lock motor (pyrolytic): If E4 appears during self-clean, the lock motor may be jammed. Access the top or front panel, locate the lock motor, and check for mechanical obstruction. Lightly lubricate the linkage if stiff.

If the door switch or lock motor is defective, replace the door lock assembly. Do not bypass safety switches; they prevent operation with an open door.