Daewoo Microwave Error Code Err 3

Err 3 means the control board has detected a fault in the thermistor circuit. The thermistor is a temperature-sensing component that should read approximately 200k to 300k ohms at room temperature. If it reads 0 ohms or infinite resistance, the board cannot monitor internal temperature and shuts the unit down. A wiring harness fault or heater circuit failure can also trigger this code.

No. The microwave has disabled itself because it cannot monitor internal temperature, which is a safety function. Operating the unit without a working thermistor circuit could allow components to overheat without detection. Do not attempt to bypass the error or force the unit to run until the fault is diagnosed and repaired.

If the thermistor itself is the problem, parts are generally inexpensive, typically in the range of a few dollars to around twenty dollars depending on the model. If a professional technician is needed for diagnosis and replacement, labor costs typically bring the total repair into the range of fifty to one hundred fifty dollars. More complex faults involving the heater circuit or control board can increase that cost significantly, and it may be worth comparing repair cost to the price of a replacement unit.

A knowledgeable DIYer can diagnose this error using a multimeter to check the thermistor resistance. If the reading is 0 ohms or infinite at room temperature, the thermistor needs to be replaced. Wiring and connector issues can also be addressed without professional help, but any work inside a microwave should be done with the unit unplugged and after discharging the high-voltage capacitor, which can hold a lethal charge even when the power is off.

A power reset by unplugging the unit for a few minutes may temporarily clear the display, but the error will return as soon as the control board re-checks the thermistor circuit. Err 3 indicates a hardware fault, so a reset alone will not fix the underlying problem. The thermistor, wiring, or heater circuit must be inspected and repaired to resolve the code permanently.