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Error code reference

Daewoo Air Conditioner Error Code CODE3

Outdoor (O/D) sensor open or short circuit

Daewoo codesDaewoo air conditioner codes

Outdoor (O/D) sensor open or short circuit - unit does not work.

First step from the service manual

Check O/D sensor resistance and connection.

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

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  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
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What CODE3 means on a Daewoo air conditioner

CODE3 on a Daewoo air conditioner indicates a fault with the outdoor unit ambient temperature sensor, commonly called the O/D sensor. This thermistor monitors the temperature of the air surrounding the outdoor unit and feeds that data to the main control board. When the board detects an open circuit or a short circuit in the sensor circuit, it interprets the reading as outside the valid operating range and shuts down the unit entirely to prevent potential damage from operating under unknown ambient conditions.

An open circuit condition means the sensor circuit has lost continuity, typically due to a broken wire, corroded connector, or a failed thermistor that has drifted to infinite resistance. A short circuit condition means the sensor or its wiring has collapsed to near-zero resistance, often caused by pinched wiring, moisture intrusion into the connector, or a thermistor that has failed internally. In both cases, the control board cannot obtain a valid temperature reading and flags the fault.

The first diagnostic step is to measure the O/D sensor resistance and inspect its wiring harness and connector. A properly functioning NTC thermistor will show a specific resistance value that corresponds to the current ambient temperature. A reading of zero ohms or infinite ohms confirms the sensor has failed or the circuit is broken. Inspecting the connector for corrosion, moisture, or loose terminals should be performed alongside the resistance measurement before replacing any components.

Source: manufacturer service documentation.

Common causes of CODE3

  1. 01

    Failed outdoor temperature sensor

    Part replacement

    The thermistor itself has failed, producing either infinite resistance (open) or zero resistance (short). Measuring the sensor resistance directly will confirm this if the reading falls well outside the expected range for the current ambient temperature.

  2. 02

    Corroded or loose sensor connector

    Wiring / connection

    Moisture and outdoor exposure can cause the sensor connector to corrode or pull loose, breaking the circuit. Visually inspect the connector at the sensor and at the control board for oxidation, bent pins, or a connector that is not fully seated.

  3. 03

    Damaged sensor wiring harness

    Part replacement

    The wiring between the outdoor sensor and the control board can become pinched, cut, or abraded over time, particularly where it passes through panels or conduit openings. A continuity check along the harness will reveal any break.

  4. 04

    Moisture intrusion into the sensor body

    Part replacement

    Water entering the sensor housing can cause an internal short circuit. This is more common in units exposed to heavy rain or high humidity. The sensor housing should be inspected for cracks or evidence of water ingress.

  5. 05

    Faulty main control board

    Part replacement

    If the sensor and all wiring check out within normal resistance values, the control board input circuit may have failed and is misreading the signal. This is the least likely cause and should only be considered after the sensor and harness are confirmed good.

See the test procedure for each cause

Frequently asked questions about CODE3

What does CODE3 mean on a Daewoo air_conditioner?
CODE3 indicates that the outdoor ambient temperature sensor has been detected as either open circuit or short circuit. The control board cannot receive a valid temperature reading from the sensor and has shut the unit down as a result. The fault covers both a broken circuit and a collapsed short in the sensor or its wiring. The unit will not operate until the fault is resolved.
How do I fix CODE3 on my Daewoo air conditioner?
Start by inspecting the outdoor sensor connector for corrosion, moisture, or loose terminals and reseat it if necessary. Then measure the resistance of the O/D sensor and compare it to the expected value for the current ambient temperature. If the reading is infinite or zero ohms, the sensor needs to be replaced. Also check the wiring harness for any visible damage between the sensor and the control board.
Will resetting my Daewoo air conditioner clear CODE3?
A power reset may temporarily clear the error code display, but CODE3 will return as soon as the system restarts and re-checks the sensor circuit. Because the fault reflects an actual electrical condition in the sensor or wiring, it will not resolve on its own without physical repair. Resetting without addressing the root cause will not restore normal operation.
Is it safe to use my Daewoo air conditioner while CODE3 is active?
The unit will not operate while CODE3 is active, so there is no risk of running it in a damaged state. The system is designed to shut down completely when this fault is detected. There is no safety hazard to the home from the fault itself, but the unit should be repaired before attempting to restore operation.
How much does it cost to repair a CODE3 error on a Daewoo air conditioner?
If only the connector or wiring needs attention, repair costs may be minimal, covering primarily labor time. If the outdoor temperature sensor itself needs replacement, parts and labor costs typically range from around 50 to 200 dollars depending on your location and service provider. If the fault has caused control board damage, costs will be higher. Getting a diagnostic assessment from a qualified technician before purchasing parts is recommended.

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