E12 Moderate Moderate DIY
Bosch Washer E12 — Temperature Sensor (NTC) Fault
Bosch Washer · Error code E12
What E12 Means
The NTC thermistor that monitors wash water temperature is reporting out-of-range values, often a short or open circuit.
Symptoms
- Hot wash not heating
- Cycle aborts after fill
- Long wash times
- Cold water on all temperature settings
Common Causes
1
NTC sensor failure
Thermistor element broken, reads open or shorted.
2
Wiring break to NTC
Lead between sensor and main board damaged.
3
Corroded NTC connector
Moisture in connector raises resistance.
4
Heating element NTC integrated unit failed
On models where NTC clips into the heater body.
How to Fix It
- Unplug the washer and access the heating element area.
- Locate the NTC (usually built into or beside the heater flange).
- Disconnect and measure resistance at room temperature (~10k ohms is typical).
- Replace the NTC if reading is open, shorted, or wildly off.
- Inspect the wiring back to the control board; repair as needed.
- Restore power and run a hot cycle to verify.
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.
More Bosch Washer Codes
Verified against manufacturer documentation: bosch-home.com
Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician.