Samsung Refrigerators2017–present

Error Code 4

Freezer defrost sensor is not responding or is broken

Critical

Stop using immediately - risk of damage or safety issue

Also displayed as: F-Def Sensor Error

What This Means

Defrost sensor disconnected or damaged; Wire cut or short circuit; Sensor mounted incorrectly on evaporator; Temperature reading anomaly

What actually causes this:

Defrost cycle sensor damage or connection failure

First Thing to Check

Check connector pins at DC BLU1 for corrosion or loose fit

Parts Involved

Freezer Defrost SensorEvaporatorDC BLU1 Connector

How to Fix

  1. 1

    Check voltage between Case Connector DC BLU1 #14 and #15

  2. 2

    Expected voltage should be within 4.5V to 1.0V

  3. 3

    Verify sensor is properly mounted on freezer evaporator

  4. 4

    Test sensor response during defrost cycle

This Error Applies To

Samsung BRF425200A Series Refrigerators (2017) (2017–present)

Service manual exact match: BRF425200AP/AAService manual exact match: DRF427500AP/DAService manual exact match: DRF429900AP/DAService manual exact match: DRF425300AP/DA

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