If the oven turns on and food just comes out wrong, the most common cause is a failing temperature sensor or an oven that has drifted out of calibration, both fairly simple fixes. If the oven produces no heat at all, the cause depends on the type, a failed bake or broil element on electric models, or a failed igniter or gas valve on gas models.
When an oven turns on, the display lights up, and it runs for the full cook time, but the food comes out underdone, burned, or barely warm, it is easy to assume the whole unit needs replacing. In practice, the issue is usually narrow, a sensor reading the wrong temperature or a calibration setting that has drifted, sitting alongside a smaller set of causes that genuinely need a licensed technician.
Below are the eight causes we see most often, ordered from most to least common, along with the signs that separate one from another and an honest answer on whether it is safe to check yourself. A few causes only apply to one fuel type, so knowing whether your oven is gas or electric will help narrow things down faster.
Jump to a cause
Faulty temperature sensor
The temperature sensor, usually a thin metal probe inside the cavity, tells the control board how hot the oven actually is. When it reads inaccurately or touches the oven wall, the control board over- or under-corrects, so the display shows the right number while the real temperature is off.
- Food is consistently underdone or overdone at the correct time and setting
- The sensor probe looks like it is touching the oven wall
- Results have gotten steadily less reliable over recent months
- An oven thermometer placed inside reads noticeably different from the display
Oven needs calibration
Ovens can drift a little hotter or cooler than their setting over years of use. Most models have a built-in calibration offset in the settings menu specifically to correct this, and it is one of the most overlooked fixes for consistently off results.
- Results are consistently a bit too hot or too cold, not wildly wrong
- The oven has never been calibrated since it was installed
- The problem showed up gradually, not suddenly
- An oven thermometer confirms a steady, predictable offset
Door not sealing properly
A worn, torn, or dirty door gasket lets heat escape during cooking. The oven keeps calling for more heat to compensate, which can throw off timing, cause uneven results, and extend cook times well beyond the recipe.
- Visible cracks, flattening, or gaps in the rubber door gasket
- Heat or warmth noticeable around the door edge while baking
- Cook times run longer than the recipe calls for
- The door does not sit flush or latch as firmly as it used to
Failed bake or broil element (electric)
Electric ovens use separate coiled elements for baking and broiling. When one burns through or develops a weak spot, it may glow unevenly, cycle oddly, or stop producing heat altogether, while the other element and the rest of the oven keep working normally.
- This is an electric oven, not a gas model
- The bake or broil element does not glow red when it should
- Visible blistering, bubbling, or a break in the element coil
- One function, bake or broil, works fine while the other does not
Failed igniter or gas valve (gas)
Gas ovens use an electric igniter that has to glow hot enough to open the safety valve and light the burner. A weak igniter may glow but never get hot enough, leaving the oven to run without ever actually heating.
- This is a gas oven, not an electric model
- No burner ignition sound or smell of gas during preheat
- The igniter glows weakly or takes unusually long to click on
- The stovetop burners, if separate, still work normally
Convection fan not running
On convection models, a fan circulates hot air around the cavity for even cooking. When it stops running, heat pools near the element instead of spreading evenly, so one side or rack cooks faster than another even though the oven still heats.
- This oven has a convection setting
- No fan sound or airflow felt near the vents during convection mode
- One rack or side of the oven cooks noticeably faster than another
- Regular bake mode, if available, performs more evenly than convection
Faulty thermostat or control board
The thermostat or control board manages when the heating elements or burner cycle on and off to hold the set temperature. When it fails, the oven can overshoot, undershoot, or cycle unpredictably regardless of how accurate the sensor itself is.
- Temperature swings noticeably during a single bake, not just between bakes
- The sensor has already been checked and tested fine
- Other electronic functions, like the timer or display, behave oddly too
- The oven sometimes overheats or undershoots dramatically, not just slightly
Blown thermal fuse or tripped breaker
A thermal fuse cuts power to the heating circuit if the oven overheats, and it does not reset itself once blown. On electric models, a tripped breaker on either leg of a 240-volt circuit can also cut off just the heating function while lights and controls still work.
- The oven turns on, the display works, but there is no heat at all
- The problem appeared suddenly rather than gradually
- The breaker panel shows one side of a double breaker tripped
- The interior light and fan, if equipped, still work normally
Not sure which one matches? Start here
Oven runs, but food is always undercooked or overcooked
- Most likely: temperature sensor or calibration drift
- Also check: the door seal
Oven does not heat at all
- Most likely: bake or broil element (electric) or igniter or gas valve (gas)
- Also check: thermal fuse or breaker
Not sure which one it is?
Skip the guesswork. Tell us what you're seeing and a technician will help pin down the cause.
What to check yourself first
These items are safe to check without any tools beyond an oven thermometer. Never attempt to inspect or reset gas components yourself.
If you ever smell gas near the oven, leave the area and contact your gas utility before doing anything else.
Test with an oven thermometer. Place one inside and compare its reading to the display after preheating.
Check the calibration setting. Look in your owner's manual for how to adjust the temperature offset.
Inspect the door gasket. Look for cracks, gaps, or spots where it no longer sits flush.
Look at the breaker panel. On an electric oven, confirm both sides of the double breaker are fully reset.
Note the oven type. Knowing whether it is gas or electric narrows down which causes above apply.
When to call a professional
Some signs point straight to a licensed technician rather than a DIY fix. Call for service if you notice any of the following:
- Any smell of gas near the oven
- A burning smell, scorch marks, or visible sparking
- A breaker that trips repeatedly after being reset
- You have checked calibration, the seal, and the breaker and results are still off
- The oven is still under manufacturer warranty, since a DIY repair can void it
Revive Appliance Repair handles oven heating and temperature issues for gas and electric models throughout Walnut Creek and the surrounding service area. Our oven repair service covers diagnosis through completed repair, backed by a 90-day labor warranty.
You may also find these guides useful: troubleshooting a stove burner that won't light and a microwave that is not heating.