What Bosch ER1 error means on your range
The Bosch ER1 error indicates a fault with the oven temperature sensor, its wiring, or the control module in a Bosch range. The oven section of the range cannot accurately read or control temperature. This error prevents the oven from heating to avoid uncontrolled temperature conditions. ER1 is functionally similar to ER4 on standalone Bosch wall ovens.
Symptoms
- The range oven displays ER1 and will not heat
- The cooktop burners may still work normally (they have separate controls)
- The oven may have been heating erratically before the error appeared
- Self-clean function will not engage
Common causes
- Failed temperature sensor (RTD) — the platinum resistance probe inside the oven cavity has degraded from heat exposure
- Damaged sensor wiring — the wire between the sensor and control board passes through the oven wall and can break from thermal cycling
- Control module fault — the analog-to-digital converter on the control board that reads the sensor signal has failed
Troubleshooting steps you can try
- Power reset — turn off the breaker for 10 minutes. A temporary reading glitch can sometimes clear.
- Test the sensor — locate the sensor probe (a thin metal rod inside the oven, usually at the top or back). Disconnect the plug at the rear of the range and measure resistance with a multimeter. At room temperature, a working sensor reads approximately 1,080–1,100 ohms. Check Bosch range support for model-specific specifications.
- Inspect the sensor physically — look for a bent, broken, or discolored probe, and check that it’s not touching the oven wall.
When to call a technician
If the sensor tests outside normal range, it needs replacement — an inexpensive repair. If the sensor tests normal but ER1 persists, the control module’s sensor input circuit has likely failed, requiring board replacement. Schedule Bosch range service. Our range repair technicians carry sensor probes and can diagnose board issues. See all Bosch range error codes.
