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Error code reference

GE Range Error Code 300

Cavity 1 thermal runaway when locked

GE codesGE range codes

Cavity 1 thermal runaway when locked — cavity temperature exceeds 950°F with the door locked (i.e., during self-clean).

First step from the service manual

Press cancel to reset system. Check RTD sensor; system may be overheated.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What 300 means on a GE range

Error code 300 on a GE range indicates a cavity thermal runaway condition in Cavity 1 while the door is locked. Specifically, the oven cavity temperature has exceeded 950 degrees Fahrenheit during a self-clean cycle. The self-clean function intentionally operates at very high temperatures to incinerate food residue, typically in the 800 to 900 degree Fahrenheit range. When temperatures climb beyond 950 degrees with the door locked, the control board registers this as an uncontrolled or runaway heating event and triggers the fault code to protect the appliance and user.

The component most directly involved in detecting this condition is the RTD (Resistance Temperature Detector) sensor, also called the oven temperature sensor. This sensor continuously monitors cavity temperature and feeds resistance data back to the control board. As temperature rises, resistance changes in a predictable pattern. If the RTD sensor is reading incorrectly due to a fault or partial failure, the control board may either receive inaccurate temperature data or lose the ability to regulate the heating elements properly, allowing temperatures to climb unchecked beyond safe operating limits.

Thermal runaway can also result from a failed relay on the control board that keeps a bake or broil element energized without command, or from a shorted heating element drawing continuous power. In any of these cases, the oven cannot regulate its own temperature. The first step is to press Cancel to reset the system and release the door lock. After cooling completely, the RTD sensor should be tested for proper resistance values and inspected for physical damage before attempting another self-clean cycle.

Source: manufacturer service documentation.

Common causes of 300

  1. 01

    Faulty RTD Temperature Sensor

    Part replacement

    A failing RTD sensor can send inaccurate resistance readings to the control board, causing the oven to misjudge cavity temperature and allow heating elements to run beyond safe limits. Test the sensor's resistance at room temperature and compare to spec; a reading that is out of range or erratic confirms sensor failure.

  2. 02

    Stuck Relay on the Control Board

    Part replacement

    A welded or stuck relay on the electronic control board can keep a bake or broil element continuously energized regardless of the control signal, causing uncontrolled temperature rise. If the oven heats without command or the error recurs after sensor replacement, the control board is the likely culprit.

  3. 03

    Shorted Bake or Broil Heating Element

    Part replacement

    A shorted element can draw continuous power and generate heat even when the control board is not commanding it, contributing to a runaway temperature condition. Inspect elements visually for burn marks, blistering, or breaks, and test for continuity and resistance.

  4. 04

    Overloaded or Excessively Soiled Oven Cavity

    Wiring / connection

    An extremely heavy buildup of grease or food debris can generate significant additional heat during self-clean, pushing cavity temperatures higher than the control system expects. Manually cleaning heavy residue before running self-clean reduces the thermal load on the cycle.

  5. 05

    Loose or Corroded RTD Sensor Wiring

    Wiring / connection

    Damaged wiring connections at the RTD sensor or at the control board can cause intermittent or erratic resistance readings, leading the system to misread cavity temperature. Inspect the sensor harness connectors for corrosion, heat damage, or loose pins.

See the test procedure for each cause

Frequently asked questions about 300

What does 300 mean on a GE range?
Error code 300 on a GE range means the oven cavity temperature exceeded 950 degrees Fahrenheit while the door was locked during a self-clean cycle. The control board detected a thermal runaway condition, meaning the oven temperature climbed beyond safe operating limits without being controlled. The oven shuts down automatically as a safety measure. The RTD temperature sensor and the control board are the primary components to inspect when this code appears.
Is it safe to use my GE range after a 300 error code?
You should not run the self-clean cycle again until the cause of the error has been identified and repaired. Normal baking and cooking may be possible once the oven has fully cooled and been reset, but a thermal runaway fault indicates a real control or sensing problem that needs attention. Operating the oven in self-clean mode before the issue is resolved risks additional overheating. Allow the oven to cool completely, press Cancel to reset it, and consult a technician before running another self-clean cycle.
Will pressing Cancel or resetting the oven clear the 300 error code?
Pressing Cancel will reset the system and release the door lock, and the error code should clear. However, resetting the control does not fix the underlying problem that caused the thermal runaway in the first place. If the RTD sensor is faulty, a relay is stuck, or an element is shorted, the code is likely to return the next time self-clean is run. Use the reset only as a first diagnostic step, not as a permanent fix.
How do I fix a 300 error code on a GE range?
Start by pressing Cancel to reset the system and allowing the oven to cool fully. Once cooled, test the RTD temperature sensor for proper resistance and inspect its wiring harness for damage or loose connections. If the sensor tests within spec, the control board should be evaluated for a stuck relay. A shorted heating element is another possible cause and can be tested for continuity. Depending on which component is faulty, repairs involve replacing the RTD sensor, the control board, or the heating element.
How much does it cost to repair a GE range with a 300 error code?
Repair costs vary depending on which component has failed. An RTD temperature sensor is generally the least expensive fix, with parts typically ranging from around 20 to 60 dollars plus labor. A replacement electronic control board is more costly, with parts often ranging from 150 to 350 dollars or more depending on the model, plus labor. If a heating element is the cause, parts usually fall in the 30 to 100 dollar range. Total repair costs including professional labor can range from roughly 100 to 500 dollars or more depending on the diagnosis.

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