The 42E error on your Samsung Washer means the machine has detected a problem with a water temperature sensor circuit during a wash cycle. This is usually caused by a faulty sensor, a damaged wiring harness, or a control board fault, and it can often be checked and fixed without calling an engineer.

Error code 42E
Meaning Water temperature sensor (thermistor) circuit fault detected by the main control board
Severity Medium — the washer will usually stop mid-cycle to protect the motor and heater
Time to fix 15–40 minutes
Tools needed Multimeter, screwdriver (Phillips or Torx depending on model)

What the 42E error means

Samsung washing machines use a thermistor to monitor water temperature throughout the wash cycle so the control board can regulate heating correctly. When the 42E code appears, the board has received an out-of-range or missing signal from this sensor, which it interprets as a fault. The machine typically pauses or stops the cycle to avoid overheating or damaging internal components.

This code is similar in nature to other sensor-related faults you may have seen on Samsung appliances, such as the Samsung Washer SE Error Code: Causes and Fixes, where a sensor communication issue also triggers a safety stop.

Common causes

  • Faulty or degraded water temperature sensor (thermistor)
  • Loose or corroded wiring connector at the sensor or control board
  • Damaged wiring harness from vibration or heat exposure over time
  • Main control board failure or firmware glitch
  • Water leak near the sensor housing causing a short circuit
  • Excessive limescale or mineral buildup affecting sensor accuracy

How to fix the 42E error

  1. Power cycle the washer — Unplug the machine for 5 minutes, then plug it back in. This clears temporary faults and resets the control board.
  2. Inspect the wiring harness — Open the back or top panel (check your model’s service guide) and look for loose, frayed, or corroded connectors leading to the temperature sensor.
  3. Test the thermistor with a multimeter — Disconnect the sensor and check resistance against the manufacturer’s spec sheet. A reading far outside range confirms a faulty sensor.
  4. Check for water leaks near the sensor — Moisture around the connector can cause short circuits. Dry the area thoroughly and reseat the connection.
  5. Replace the temperature sensor — If the thermistor fails the resistance test, replace it with a genuine Samsung part matched to your model number.
  6. Inspect or replace the control board — If the sensor and wiring test fine, the fault likely lies with the control board itself, which should be assessed by a qualified technician.

FAQ

Can I keep using the washer if 42E keeps appearing?
It’s best to stop using it until the sensor is checked, as running cycles with an unreliable temperature reading can affect wash performance and may strain the heating element.

Is the 42E error covered under warranty?
If your washer is still within its manufacturer warranty period, sensor and control board faults are typically covered — contact Samsung support with your model and serial number before attempting repairs yourself.

Do I need a professional to fix this?
Basic checks like power cycling and inspecting visible wiring are safe to do yourself. Replacing the sensor or control board requires some technical confidence and, in some cases, is best left to a certified appliance repair technician.