Bosch Oven Error Code Er1 — Temperature Sensor Failure
What this means
Error Er1 indicates the oven's temperature sensor has failed. This sensor monitors the internal oven temperature and reports it to the control board. A failed sensor causes the oven to shut down as a safety precaution since it cannot regulate temperature. Testing with a multimeter should show approximately 1,080 ohms at room temperature.
Alternate codes: E031
Step-by-step fix
4 stepsTest the sensor
Locate the temperature sensor probe inside the oven cavity (usually a thin metal rod at the back). Disconnect it and measure resistance — it should read about 1,080 ohms at room temperature.
Access the sensor connection from behind the oven or behind the control panel.
Check wiring
Inspect the wiring from the sensor to the control board for damage, loose connections, or burnt sections.
Replace the sensor
If resistance is far from 1,080 ohms or shows no continuity, replace the sensor probe. It usually mounts with one or two screws inside the oven.
The replacement is straightforward — just unscrew the old sensor and plug in the new one.
Test after replacement
Run the oven at 350°F and verify it reaches and holds the correct temperature.
When to call a professional
If the sensor tests normal but the error persists, the control board may have a faulty temperature input circuit.
Information compiled from manufacturer service manuals, official troubleshooting documentation, and appliance repair industry resources. This guide is for informational purposes only — always consult a qualified technician for complex repairs.
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