mypros+
Error code reference

GE Range Error Code F21x

Temperature inside oven cavity exceeds 900°F with door unlocked.

GE codesGE range codes

Temperature inside oven cavity exceeds 900°F with door unlocked.

First step from the service manual

a) Check for welded relay contacts. b) Check for high resistance in sensor connectors especially at sensor in rear.

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

MyPros+ Max

Get the full diagnostic procedure for F21x.

  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What F21x means on a GE range

The F21x error code on a GE range indicates that the temperature sensor inside the oven cavity has detected a temperature exceeding 900 degrees Fahrenheit while the oven door is in the unlocked position. This is a critical safety condition, as normal baking and broiling operations should never approach this threshold. The control board monitors the oven temperature sensor (RTD probe) continuously, and when the cavity temperature climbs beyond this limit without a corresponding door-lock signal, the board triggers this fault to prevent damage to the oven interior and potential fire hazard.

The two primary areas to investigate are the relay contacts on the control board and the resistance integrity of the sensor circuit. Welded relay contacts occur when a relay on the board fuses in the closed position, causing the bake or broil element to receive continuous power with no ability to cycle off. This results in runaway heating that can push the cavity temperature well past safe limits. Because the relay is physically stuck closed, the control board loses its ability to interrupt power to the heating element.

High resistance in the sensor wiring, particularly at the connector located at the rear of the oven where the probe meets the wiring harness, can also produce false high-temperature readings. Corrosion, heat damage, or loose pins at this connector alter the resistance signal sent to the control board, causing the board to interpret a normal temperature as dangerously elevated. Inspecting and cleaning these connectors, and verifying sensor resistance against the expected RTD curve, is an essential diagnostic step.

Source: manufacturer service documentation.

Common causes of F21x

  1. 01

    Welded relay contacts on the control board

    Part replacement

    A relay on the control board can fuse in the closed position, causing the bake or broil element to stay energized continuously with no ability to cycle off. This leads to uncontrolled temperature rise well beyond the 900 degree threshold.

  2. 02

    High resistance at the rear sensor connector

    Wiring / connection

    Corrosion or loose pins at the wiring harness connector near the oven temperature sensor at the rear of the unit can skew the resistance signal, causing the board to read a falsely elevated temperature. Inspect and clean this connector and check for proper pin seating.

  3. 03

    Faulty oven temperature sensor (RTD probe)

    Part replacement

    A damaged or out-of-spec temperature sensor can report incorrect resistance values to the control board, triggering a false over-temperature fault. Verify the sensor resistance at room temperature and compare it to the expected value for the probe.

  4. 04

    Damaged sensor wiring harness

    Part replacement

    Wiring between the temperature sensor and the control board can suffer heat damage, fraying, or shorts over time. Any break or degradation in this circuit can produce erratic or extreme resistance readings interpreted as an over-temperature condition.

  5. 05

    Failing control board

    Part replacement

    If relays and sensor components test within spec but the fault persists, the control board itself may be misreading sensor input or failing to properly regulate power to the heating element. This is typically the last component to suspect after ruling out the others.

See the test procedure for each cause

Frequently asked questions about F21x

What does F21x mean on a GE range?
The F21x code on a GE range means the control board has detected a temperature inside the oven cavity exceeding 900 degrees Fahrenheit while the door is unlocked. This is a safety fault that halts oven operation. It typically points to a welded relay on the control board that is keeping the heating element on continuously, or to a high-resistance connection at the temperature sensor wiring near the rear of the oven.
Is it safe to use my GE range while the F21x error is displayed?
No, you should not use the oven while this fault is active. The F21x code indicates a potential runaway heating condition, which poses a fire risk and could cause serious damage to the oven interior. Disconnect power to the range and do not operate it until the underlying cause, whether a welded relay or a faulty sensor circuit, has been identified and corrected.
Will resetting my GE range clear the F21x error code?
Resetting the range by cutting power at the breaker may temporarily clear the displayed fault, but it will not resolve the underlying problem. If the cause is a welded relay contact, the element will continue to receive uncontrolled power once the oven is restarted and the fault will return. A proper diagnosis of the relay contacts and sensor connectors is required before the range can be safely used again.
How do I fix the F21x error on a GE range?
Start by inspecting the relay contacts on the control board for signs of welding or fusing in the closed position. Next, check the wiring harness connector at the temperature sensor near the rear of the oven for corrosion, high resistance, or loose pins. If the connector and wiring check out, test the RTD temperature sensor itself for correct resistance values. Depending on what is found, the repair will involve replacing the control board, the sensor, or repairing the wiring connection.
How much does it cost to repair a GE range showing the F21x error?
Repair costs vary depending on the failed component. A replacement oven temperature sensor typically runs in the range of $20 to $60 for the part. A control board replacement is more expensive, generally in the range of $150 to $350 or more for the part alone. Adding professional labor costs can bring the total repair anywhere from $150 to $500 or higher, depending on your location and the specific component that needs to be replaced.

Related GE range codes

All GE range codes
View all 303 GE range codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass