tO Serious Moderate DIY

Samsung Dryer tO — Thermistor Open Circuit

Samsung Dryer · Error code tO

What tO Means

The drum thermistor circuit is reading open — either the sensor failed, a wire broke, or the connector came loose. Dryer can't measure drum temperature safely.

Symptoms

  • tO at cycle start
  • No heat throughout cycle
  • Cycle aborts after a few minutes

Common Causes

1
Failed thermistor (open)

Sensor element failed internally — reads infinite resistance.

2
Disconnected thermistor harness

Connector vibrated loose at sensor or at control.

3
Broken thermistor wire

Wire fatigued and snapped near a chafe point.

4
Corroded sensor terminals

Moisture corrosion breaking the circuit.

How to Fix It

  1. Unplug dryer and access the blower housing thermistor.
  2. Verify the harness connector is fully seated at the sensor and at the main board.
  3. Measure thermistor resistance — should be ~10K ohms cold. Open reading = replace.
  4. Inspect the full harness run for breaks, especially at hinge / strain points.
  5. Replace the thermistor and any damaged wiring.
  6. Reassemble and run a sensor dry cycle to confirm temperatures track correctly.

Parts You May Need

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

Common replacement Drum thermistor View on Amazon→

More Samsung Dryer Codes

3C 3C Error — Motor Error 9E1 9E1 / 9C1 — Power Supply / Voltage Error AC AC / AE — Communication Error Between Boards bE bE / bE2 — Button / Key Stuck C8 C8 — Lint Filter / Vent Reminder C80 C80 / C90 — Vent Blockage Detected

All Samsung codes → All dryer codes →

Verified against manufacturer documentation: samsung.com

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician.