Frigidaire Range Error Code 3d21

Error code 3d21 means the oven temperature sensor in that cavity has shorted and is reading 0 ohms of resistance. Because the oven cannot measure temperature accurately under this condition, it disables all cook functions for that cavity and flashes the BAKE indicator on the display. The fault points to either a failed sensor, damaged wiring, or a problem at the sensor connector.

The oven automatically disables all cooking functions in the affected cavity when 3d21 is active, so the oven will not heat in that mode regardless. Surface burners on a gas or electric range are typically unaffected by this fault. It is best to resolve the error before attempting to use the oven, since operating without a functioning temperature sensor would make temperature control impossible.

If the oven temperature sensor is the cause, replacement sensors typically cost in the range of $20 to $60 for the part, depending on the specific model. If professional repair service is needed, total costs including labor generally fall in the range of $100 to $250. Wiring or connector repairs may cost less if no parts are needed, but labor charges still apply when a technician performs the work.

A knowledgeable DIYer can diagnose this fault by disconnecting the sensor from its wiring harness and checking resistance across the sensor leads with a multimeter. A reading of approximately 1080 ohms at room temperature indicates the sensor is good and the wiring or connector needs attention. If the sensor reads 0 ohms when disconnected from the harness, the sensor itself needs to be replaced. Replacing the sensor is generally a straightforward repair involving a single mounting screw and a wire connector.

Resetting the range by cutting power at the breaker or unplugging it may temporarily clear the display, but the code will return as soon as the control checks the sensor circuit again if the underlying short is still present. A reset does not repair a shorted sensor or damaged wiring. The fault must be corrected at the component level to permanently clear the code.