Measure the cavity with an independent thermometer
Put an oven thermometer on the centre shelf, set a moderate temperature, and let everything settle for a while before reading it. A cavity that arrives close to the setting is heating correctly and the complaint is about something else. A cavity that sits well below it is either losing heat or being told to stop too early, and those are different faults.
What you find
- Food undercooks consistently at settings that used to work — The signature of a cavity running below its setting rather than not heating.
- The oven signals ready but the cavity is still cool — Sensing that reports temperature too high, which stops the call for heat early.
- Baking is poor while grilling browns normally — Different elements, and it points at one of them rather than at the cavity.
- The cavity never gets warm on any setting — A genuine no-heat fault, which is the other branch.
- Long preheat times with heat escaping around the door — A sealing problem, which no calibration will fix.
- NEAR MISS: results that changed after a new cookware set — Heavy or dark tins change cooking times substantially and are not a fault.
Ranked for a cavity that underperforms
- Calibration drift — First when the oven heats but underdelivers. Many controls offer an adjustment for exactly this, and a modest offset restores the results people remember.
- A temperature sensor reading high — Second. It tells the control the cavity is hotter than it is, so heating stops early and the results are consistently pale.
- A door that no longer seals — Third. It produces the same undercooking by losing heat rather than by failing to make it.
- A failed element — First for the no-heat branch, and identified by which functions still work.
Measure, then decide which branch
- Measure the settled cavity temperature against the setting — It is the only way to separate a real fault from an expectation.
- Note whether grilling and baking behave differently — It identifies an element fault, which calibration cannot help.
- Check the door seal and hinge if preheats are long — A leaking cavity needs a seal, not an offset.
- Use the control's own calibration adjustment if one exists — It is the correct response to a small consistent offset with everything else healthy.
Owner steps
- Place an oven thermometer on the centre shelf and set a moderate temperature — Let it settle for a good while before reading; cavities swing either side of the setting.
Tools: oven thermometerAbout 45 min
- Read the thermometer several times over the next stretch and note the range — A single reading is not enough; you are looking for where it settles on average.
Tools: notepadAbout 30 min
- Try baking and grilling separately and compare the results — Different functions use different elements, which separates a cavity problem from a part failure.
About 30 min
- Look up the calibration adjustment in the manual and apply a modest offset — This is the designed response to a small consistent difference, and it is reversible.
About 15 min
- STOP before the rear cover, the sensor or any element connection is touched — Mains voltage and a heating circuit sit behind them, and that is the boundary.
Before anything is opened
Safety
Unplug the appliance or switch off its breaker before removing any cover, and let the cavity cool completely first. Do not leave a glass thermometer in a cavity during a self-clean cycle, and do not run self-clean to test an oven that is already misbehaving. Stop immediately if you see sparking at an element or smell burning.
When to call
Call if the cavity sits far below the setting, if one function produces no heat at all, or if the difference is too large for the calibration adjustment to cover. Call immediately for sparking or burning smells. Bring the thermometer readings: an oven measured against a setting is a far quicker diagnosis than one described from its results.
Nearest pages of this class
Scope of this page
Written for the LG oven class rather than one model line. Calibration ranges, element arrangements and sensor positions differ by family, and the adjustment procedure belongs on the page for your specific appliance.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
