Samsung · Dryer Serious
tO — Thermistor Open Circuit
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.
- Keep using it?
- Limited use only
- DIY difficulty
- Moderate
- Verified against
- samsung.com ↗
How to fix it
- Unplug dryer and access the blower housing thermistor.
- Verify the harness connector is fully seated at the sensor and at the main board.
- Measure thermistor resistance — should be ~10K ohms cold. Open reading = replace.
- Inspect the full harness run for breaks, especially at hinge / strain points.
- Replace the thermistor and any damaged wiring.
- Reassemble and run a sensor dry cycle to confirm temperatures track correctly.
Why it happens
Typical signs: tO at cycle start · No heat throughout cycle · Cycle aborts after a few minutes
- Failed thermistor (open) Sensor element failed internally — reads infinite resistance.
- Disconnected thermistor harness Connector vibrated loose at sensor or at control.
- Broken thermistor wire Wire fatigued and snapped near a chafe point.
- Corroded sensor terminals Moisture corrosion breaking the circuit.
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.
- Drum thermistor Common replacementAmazon →
More Samsung dryer codes
Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: samsung.com.