Maytag Range Error Code 3d21

Code 3d21 means the control board detected a short circuit in the upper or single oven cavity temperature sensor. The sensor's resistance has dropped to approximately 0 ohms, which is not a valid reading. The board cannot determine oven temperature under this condition and disables the oven to prevent unsafe operation.

No. When code 3d21 is active, the oven cavity involved cannot regulate temperature because the control board has no valid sensor data. Running the oven without functional temperature control creates a risk of overheating and is not safe. Surface burners on a gas or electric range may still function, but the affected oven should not be used until the sensor or wiring fault is resolved.

Power off the range and allow the oven to cool completely. Pull the range away from the wall and access the sensor connector, which is usually routed through the rear panel. Disconnect the sensor from the harness and set a multimeter to measure resistance (ohms). Touch the probes to the two sensor terminals. At room temperature, a good sensor reads approximately 1,000 to 1,100 ohms. A reading near 0 confirms the sensor has an internal short and needs to be replaced.

Start by testing the oven temperature sensor resistance with a multimeter. Disconnect the sensor from the wiring harness and measure resistance across its two terminals. A working sensor reads roughly 1,000 to 1,100 ohms at room temperature, not near 0. If the reading is near 0, replace the sensor. If the sensor tests correctly, inspect the wiring harness between the sensor and control board for any shorts or damaged insulation.

An oven temperature sensor is typically a low-cost part, often ranging from $20 to $60 depending on the specific Maytag model. Replacing it yourself is generally a simple repair requiring only a screwdriver and takes under 30 minutes in most cases. If a wiring harness replacement or control board is needed instead, parts and labor costs rise significantly. A professional service call typically adds $80 to $150 in labor on top of part costs.