Baking is where oven faults surface first, because a cake tolerates about ten degrees of error and a roast will forgive fifty. If yours has started running cool, hot, or wildly inconsistent, three checks separate a five-minute adjustment from a real repair.
Step one: measure it, do not guess
Put an oven thermometer on the centre rack, set the oven to 350 °F, and let it run for a full twenty-five minutes — long enough for the cycling to settle. Then read it every five minutes for another fifteen.
- •Steady, but consistently off by 15 to 40 degrees. That is calibration. Nearly every oven has an offset adjustment in the control settings; consult the manual for the key sequence. Free fix.
- •Swinging 40 degrees or more either side of the set point. That is a sensor or control problem, not calibration.
- •Never reaches temperature at all. Element, igniter or control relay.
Electric ovens: element or relay
A failed bake element usually shows itself — a visible break, a blister, or a bright spot where it has arced. But an element can also fail closed-circuit-looking while drawing no current, and the control board relay that switches it can weld shut or fail open. We meter the element and watch the relay switch rather than replacing on appearance, because those two faults present identically to a customer and differ by a couple of hundred dollars.
Note that on most electric ovens the broil element handles the top of the cavity, so an oven that broils fine but will not bake has told you exactly which element to look at.
Gas ovens: watch the igniter
The sequence is worth knowing. The igniter glows, draws increasing current, and the gas valve only opens when that current crosses a threshold. As igniters age they still glow — visibly, brightly — while drawing too little current to open the valve. So "the igniter lights up, so it must be the valve" is one of the most expensive wrong conclusions in appliance repair.
If your gas oven glows for ninety seconds and then never lights, the igniter is the most likely part, not the valve.
The temperature sensor
Nearly all modern ovens use a resistance sensor at the back of the cavity. Cold, it should read close to 1,080 ohms; the resistance climbs as the oven heats. A sensor that has drifted out of spec makes the control believe the oven is hotter than it is, so the oven under-shoots and everything comes out pale. It is an inexpensive part and a quick job — the diagnosis is what matters.
Self-clean, and why we mention it
High-temperature self-clean cycles are hard on ovens. The cavity runs far above normal, and it is the single most common trigger for a thermal cutout tripping or a control board failing on an older range. If your oven died during or just after a self-clean, that is not a coincidence, and it is worth saying when you book.
Our advice on older ranges: clean by hand, or use the lowest steam-clean option if you have one.
Costs and expectations
Sensors and igniters generally land between $180 and $300 with labor; bake elements similar; control boards run higher, typically $290 to $470 depending on model. Professional ranges — Wolf, Viking, Thermador, La Cornue — sit above those bands, and we tell you where you stand before we come out rather than after.