GE Microwave Error Code Upper Thermal Sensor SHORTED

This error means the Smart Board has detected a short circuit in the upper thermistor circuit, which monitors temperature inside the microwave. The thermistor, connected at Smart Board connector CN09 via blue and white wires, should read approximately 100K ohms at room temperature. A reading far below that value indicates the sensor or its wiring has failed. The microwave disables itself when this fault is detected to prevent unsafe operation.

No, you should not continue using the microwave while this error is active. The upper thermistor is a safety-critical component that protects the unit from overheating. Operating the microwave without a functioning thermal sensor could result in overheating, component damage, or a fire hazard. The unit should remain unplugged until the fault is diagnosed and repaired.

If only the thermistor needs replacement, parts typically cost in the range of $15 to $50 depending on the specific model. If a professional technician performs the repair, labor costs generally bring the total to somewhere between $100 and $200. If the Smart Board is also found to be faulty, repair costs can rise significantly, and it may be worth comparing the repair cost against the price of a replacement unit.

A knowledgeable DIYer with a digital multimeter can perform the initial diagnosis by checking resistance at connector CN09 after unplugging the microwave. If the thermistor reads near zero ohms when disconnected, replacing the thermistor is the likely fix. However, microwaves contain high-voltage capacitors that can retain a lethal charge even after being unplugged, so internal work should only be done by those familiar with high-voltage appliance safety procedures.

A power reset may temporarily clear the error code from the display, but the fault will return as soon as the Smart Board re-evaluates the thermistor circuit. Because the error reflects an actual electrical condition, a shorted or failed thermistor, the underlying hardware problem must be corrected before the error will stay cleared permanently.