Whirlpool Oven Error Code 21

Error code 21 means the control board has detected an open circuit in the lower oven temperature sensor. The sensor, which should measure approximately 1080 ohms at room temperature, is either broken internally or has a wiring fault preventing the board from reading any temperature data. The oven will not heat safely until this fault is resolved.

No, you should not attempt to use the oven while code 21 is active. Without a functioning temperature sensor, the control board cannot regulate heat accurately, which creates a risk of overheating. The oven will typically refuse to enter a heating cycle as a safety measure until the fault is cleared.

If the temperature sensor is the cause, replacement sensors typically cost between $20 and $60 for the part alone, making it one of the more affordable oven repairs. If the wiring harness or control board is involved, total repair costs can range from $100 to $350 or more depending on parts and labor rates in your area.

Yes, this repair is within reach for a DIYer comfortable with basic electrical testing. Start by unplugging the range, then disconnect the sensor from the wiring harness and measure resistance across the two sensor pins with a multimeter. If the reading is open or far from 1080 ohms, the sensor needs replacement. If the sensor tests correctly, inspect the harness and connector for damage.

A power reset, such as unplugging the range or tripping the circuit breaker for a minute, may temporarily clear the code, but it will return as soon as the oven attempts to operate again and detects the open sensor circuit. The underlying fault in the sensor or wiring must be repaired for the code to stay cleared.