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Error code reference

Daewoo Microwave Error Code ERR 1

Thermistor short circuit detected (resistance reads 0 ohms).

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Thermistor short circuit detected (resistance reads 0 ohms).

First step from the service manual

Check continuity of thermistor (resistance of thermistor); if shorted, replace defective thermistor or PCB.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What ERR 1 means on a Daewoo microwave

ERR 1 on a Daewoo microwave indicates that the control system has detected a short circuit condition in the thermistor circuit. The thermistor is a temperature-sensing resistor responsible for monitoring internal cavity or component temperatures during cooking cycles. Under normal operating conditions, the thermistor produces a measurable resistance value that varies with temperature. When the control board reads a resistance of 0 ohms from the thermistor circuit, it interprets this as a short circuit and triggers ERR 1 to prevent potential overheating or thermal damage.

A thermistor short circuit means the resistance across the component has collapsed to zero, which signals a fault condition rather than any actual temperature reading. This can result from a failed thermistor component itself, damaged wiring in the thermistor circuit, or a fault on the PCB where the thermistor connects. Because the control board relies on accurate thermistor data to regulate cooking power and prevent overheating, a shorted thermistor will cause the microwave to shut down and display ERR 1 rather than continue operating on faulty thermal data.

Diagnosis begins by checking the continuity and resistance of the thermistor using a multimeter. A properly functioning thermistor will show a finite resistance value, not zero ohms. If the thermistor measures 0 ohms or direct continuity, the component is confirmed shorted and must be replaced. If the thermistor itself checks out as good, the fault may lie in the PCB, requiring board-level inspection or replacement.

Source: manufacturer service documentation.

Common causes of ERR 1

  1. 01

    Failed thermistor (internal short)

    Part replacement

    The thermistor component itself has developed an internal short circuit, causing it to read 0 ohms. Confirmed by measuring resistance across the thermistor with a multimeter and finding zero or near-zero ohms.

  2. 02

    Damaged thermistor wiring or connector

    Part replacement

    Wiring between the thermistor and the PCB may be pinched, burned, or have two conductors contacting each other, creating a short. Inspect the thermistor lead wires and connectors for visible damage, melting, or contact points.

  3. 03

    PCB fault at thermistor input circuit

    Part replacement

    A fault on the printed circuit board, such as a failed component or solder bridge on the thermistor input circuit, can cause the board to read 0 ohms even if the thermistor itself is functional. If the thermistor tests good but ERR 1 persists, the PCB is the likely culprit.

  4. 04

    Thermistor connector not fully seated

    Wiring / connection

    A loose or partially connected thermistor connector can in some cases create unintended continuity. Disconnect and firmly reseat the thermistor connector on the control board before replacing any parts.

See the test procedure for each cause

Frequently asked questions about ERR 1

What does ERR 1 mean on a Daewoo microwave?
ERR 1 indicates that the microwave's control board has detected a short circuit in the thermistor circuit, specifically a resistance reading of 0 ohms. The thermistor is the internal temperature sensor the microwave uses to monitor heat during operation. When a short is detected, the unit shuts down to prevent thermal damage. The thermistor itself or the PCB will need to be tested and likely replaced.
Can I reset ERR 1 on my Daewoo microwave to clear the error?
Unplugging the microwave and plugging it back in may temporarily clear the display, but ERR 1 will return as soon as the control board polls the thermistor circuit and detects the short again. The underlying fault, a shorted thermistor or PCB issue, must be repaired before the error will stay cleared.
How do I fix ERR 1 on a Daewoo microwave?
Start by testing the thermistor with a multimeter set to measure resistance. If the reading is 0 ohms, the thermistor is shorted and needs to be replaced. If the thermistor resistance appears normal, the fault is likely on the control board (PCB), which would then require inspection or replacement. Both the thermistor and PCB connections and wiring should also be visually inspected for damage.
Is it safe to use my Daewoo microwave while ERR 1 is displayed?
No, the microwave should not be used while ERR 1 is active. The error means the temperature sensor is non-functional, so the control board cannot monitor internal temperatures during a cooking cycle. Operating without a working thermistor removes a layer of thermal protection and could allow unsafe heat buildup inside the unit.
How much does it cost to repair a Daewoo microwave showing ERR 1?
If only the thermistor needs replacement, parts and labor typically cost in the range of $50 to $150 depending on the model and service provider. If the control board (PCB) is at fault, repair costs can rise to the $100 to $250 range or higher. In some cases where the microwave is older or the PCB cost is high, replacement of the entire unit may be more economical.

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