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Error code reference

Daewoo Freezer Error Code RT

RT-Sensor disconnection or short circuit.

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RT-Sensor disconnection or short circuit.

First step from the service manual

Measure the voltage between terminal PIN 1 and 2 of CN11 on the Main PCB; if under 0.5V there is a short in the sensor circuit, if over 4.7V there is an open in the sensor circuit.

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

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What RT means on a Daewoo freezer

The RT error code on a Daewoo freezer indicates a fault with the RT sensor, which is the room temperature or refrigerant temperature sensor depending on the specific model configuration. This sensor provides critical temperature data to the main PCB so the control board can regulate compressor operation and maintain proper freezer temperatures. When the control board detects a signal outside the expected voltage range from this sensor, it triggers the RT code and may limit or shut down normal operation to prevent damage.

The diagnostic process begins at connector CN11 on the main PCB, specifically between PIN 1 and PIN 2. Under normal operation, the sensor circuit produces a voltage within a defined mid-range window. A reading below 0.5V points to a short circuit condition, meaning the sensor wiring or the sensor itself has created an unintended low-resistance path to ground. A reading above 4.7V indicates an open circuit, meaning the signal path is broken and no current is flowing through the sensor. Both conditions result in the control board receiving an invalid temperature reading.

Common causes include a failed sensor with internal resistance drift to near-zero or infinite values, damaged wiring harness insulation causing a short, a loose or corroded connector at CN11, or a cracked sensor body that has broken the internal circuit. In some cases, moisture intrusion into the connector can cause intermittent shorts that trigger the code under certain humidity or temperature conditions. Addressing this fault requires systematic testing at CN11 before replacing any components.

Source: manufacturer service documentation.

Common causes of RT

  1. 01

    Failed RT sensor

    Part replacement

    The sensor itself has failed internally, causing its resistance to drop near zero (short) or climb to an open-circuit state. This produces a voltage at CN11 PIN 1 and 2 that falls outside the 0.5V to 4.7V operating range.

  2. 02

    Damaged or pinched wiring harness

    Part replacement

    The wiring between the RT sensor and CN11 on the main PCB may be pinched, chafed, or cut, creating a short to ground or an open circuit. Inspect the full length of the harness for visible damage or contact with sharp cabinet edges.

  3. 03

    Loose or corroded CN11 connector

    Wiring / connection

    A poor connection at the CN11 plug on the main PCB can cause intermittent or permanent open-circuit readings above 4.7V. Unplug and reseat the connector, then inspect the terminals for corrosion or bent pins.

  4. 04

    Moisture intrusion at the connector or sensor

    Wiring / connection

    Water or frost buildup inside the CN11 connector or around the sensor body can bridge terminals and cause a short circuit reading below 0.5V. Check for ice accumulation or condensation in the sensor area and around the connector.

  5. 05

    Main PCB fault

    Part replacement

    If the sensor and wiring both test correctly but the voltage at CN11 PIN 1 and 2 is still out of range, the main PCB itself may have a faulty sensing circuit. This is the least likely cause and should only be considered after the sensor and harness are ruled out.

See the test procedure for each cause

Frequently asked questions about RT

What does RT mean on a Daewoo freezer?
The RT code on a Daewoo freezer signals that the control board has detected a disconnection or short circuit in the RT sensor circuit. The sensor is responsible for relaying temperature data to the main PCB. A short circuit produces a voltage below 0.5V at connector CN11, while an open circuit produces a voltage above 4.7V. Both conditions cause the board to flag the RT fault.
Can I fix the RT error code myself?
Some causes of the RT code are DIY-friendly. You can start by checking that the CN11 connector on the main PCB is fully seated and that the terminals are clean and undamaged. Inspecting the sensor wiring for visible damage is also straightforward. Replacing the RT sensor or main PCB typically requires basic electrical knowledge and comfort working inside the appliance.
Is it safe to keep using my freezer while the RT code is displayed?
It is not advisable to continue relying on the freezer while the RT code is active. Without a functioning temperature sensor, the control board cannot accurately regulate the compressor, which means the freezer may run too warm and allow food to spoil, or it may not run at all. Move perishable items to another unit until the fault is resolved.
How much does it cost to repair an RT sensor fault on a Daewoo freezer?
If only the RT sensor needs replacement, parts and labor typically range from around 80 to 200 dollars depending on the technician and part availability. If the main PCB is at fault, repair costs can range from 150 to 400 dollars or more. Getting a diagnosis first helps avoid replacing parts unnecessarily.
Will resetting the freezer clear the RT error code?
A power reset may temporarily clear the RT code from the display, but the fault will return if the underlying sensor problem is not corrected. The control board continuously monitors the voltage at CN11 and will re-trigger the error as soon as it detects a reading below 0.5V or above 4.7V again. A permanent fix requires repairing or replacing the faulty component in the sensor circuit.

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