How to diagnose an oven problem?

How to diagnose an oven problem that is not heating, not baking evenly, or showing error codes requires systematic checks. First, check power and gas: for GE electric ovens like JB735SPSS, ensure breaker not tripped, outlet has 240 volts, for gas ovens, ensure gas valve behind oven open. Second, check for error codes: display may show F2 for overheating, F3 for temperature sensor failure, or F7 for control failure, note code. Third, check if oven not heating at all: for electric, test bake element at bottom and broil element at top for continuity with multimeter, if no continuity, element burned out at 30 to 80 dollars, for gas, check igniter glowing orange, if not glowing, igniter failed at 30 to 70 dollars, if igniter glows but no flame, gas valve failed. Fourth, check temperature inaccurate: use oven thermometer placed in center, set oven to 350 degrees, after preheat, thermometer should read 350 plus or minus 25 degrees, if off by more, temperature sensor probe at back wall may have failed at 20 to 40 dollars. Fifth, check door not closing: ensure door gasket not torn and hinges not bent, causing heat loss. Sixth, check uneven baking: ensure racks level and not overloading that blocks airflow. Seventh, perform hard reset: unplug oven for 10 minutes to clear control board glitches. If not comfortable with multimeter, call technician for diagnosis costing 75 to 150 dollars.