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Appliance Error Codes

Error Code Er1 on Siemens HN678G4S1 Oven | Causes & Fix

Error Er1 on Siemens : Oven temperature sensor fault — PT5000 sensor disconnected or open circuit. Follow the troubleshooting steps below to diagnose and fix this range issue. ## What Error Code Er1 Means on a Siemens HN678G4S1 Oven The Er1 error code on a Siemens oven indicates that the PT5000 PTC (Positive Temperature Coefficient) oven temperature sensor is not connected, has an open circuit, or is returning no signal. The control board uses this sensor to measure and regulate oven cavity temperature; Er1 is triggered when the sensor circuit reads outside the valid range. ## Symptoms - Er1 displayed when attempting to use the oven

  • oven will not start a baking or grilling function
  • oven temperature displayed as dashes or an error value
  • Er1 recurs immediately after a power reset ## Common Causes - disconnected sensor connector at the oven rear wall
  • broken PT5000 sensor element (normal resistance: approximately 5,000 Ω at 0°C/32°F — resistance rises approximately 0.39% per °C; at 200°C/392°F: approximately 8,900 Ω)
  • broken wire in the sensor harness between probe and control board
  • main control board temperature input circuit failure ## Tools You May Need - multimeter
  • Phillips screwdriver
  • flat-head screwdriver ## Step-by-Step Repair Guide | Step | Action | Expected Result | |------|--------|-----------------| | 1 | Turn off the oven at the circuit breaker. Open the oven door and locate the temperature sensor probe — a thin metal rod (approximately 3–4 in. long) protruding from the rear oven cavity wall. | Oven temperature sensor is located. | | 2 | Check that the probe is fully inserted into its mounting hole and that the wiring connector at the rear panel is not pulled loose. Reseat the connector if disconnected. | Sensor physical mounting and connector are confirmed. | | 3 | Access the sensor wiring connector at the rear of the oven. Disconnect and measure resistance across the two sensor terminals at room temperature (approximately 20°C/68°F). Normal PT5000 reading at 20°C is approximately 5,780 Ω. An OL reading means the sensor is open-circuit. | PT5000 sensor electrical condition is confirmed. | | 4 | If the sensor reads correctly at room temperature, measure resistance at a known elevated temperature (e.g., at 100°C/212°F the PT5000 should read approximately 6,390 Ω). A sensor that reads correctly at room temp but incorrectly at operating temperatures has drifted and needs replacement. | Sensor accuracy across temperature range is confirmed. | | 5 | If the sensor and its harness both test correctly and Er1 persists, the control board temperature input circuit has failed and the board requires replacement. | Control board fault is identified. | ## Frequently Asked Questions What is a PT5000 sensor and how does it differ from an RTD? The PT5000 is a PTC (Positive Temperature Coefficient) platinum resistance sensor with a base resistance of 5,000 Ω at 0°C. It rises predictably at approximately 0.39% per degree Celsius. At 200°C it reads approximately 8,900 Ω. This is similar to a standard PT100 or PT1000 RTD but uses a 5,000 Ω baseline. They are not interchangeable. What should the PT5000 read at room temperature? At approximately 20°C (68°F), the PT5000 sensor should read approximately 5,780 Ω. At 0°C (32°F) it reads 5,000 Ω. At 100°C (212°F) approximately 6,390 Ω. At 200°C (392°F) approximately 8,900 Ω. Can I use the stovetop or microwave while Er1 is active? On combination models, the microwave and hob functions may operate independently of the oven temperature sensor. However, all oven heating functions will be disabled until Er1 is resolved. Is Er1 safe to ignore temporarily? Er1 prevents the oven from operating at all — it will not heat until the fault is resolved. There is no safety risk from the error itself, but the oven is non-functional. --- Always turn off the oven at the circuit breaker before performing any repair. If you are unsure, contact a certified Siemens service technician or call BSH Home Appliances support at 1-800-944-2904. ### Is it safe to keep using my Siemens with error Er1? If error Er1 does not indicate an immediate safety hazard such as a gas leak, electrical short, or water flooding, you can continue limited use while monitoring the appliance. However, running the range with an active error code increases the risk of further damage. Address the underlying issue as soon as possible. For high-severity errors, disconnect the appliance and contact a qualified technician. ### How much does it cost to fix error Er1 on a Siemens ? Repair costs for error Er1 on the Siemens range depend on the root cause. DIY fixes such as cleaning filters, resetting the unit, or reconnecting loose wires cost nothing beyond basic tools. If a component replacement is needed, parts and labor from a certified technician are the main expenses. Contact a Siemens-authorized service provider for an accurate estimate based on your specific situation. ### What does error code Er1 mean on a Siemens range? Error code Er1 on Siemens range models indicates Oven temperature sensor fault — PT5000 sensor disconnected or open circuit. This error is detected by the appliance’s internal diagnostic system and displayed to alert the user that attention is needed. Refer to the troubleshooting steps above for guidance on resolving this issue. ### Is it safe to keep using my Siemens with error Er1? If error Er1 does not indicate an immediate safety hazard such as a gas leak, electrical short, or water flooding, you can continue limited use while monitoring the appliance. However, running the range with an active error code increases the risk of further damage. Address the underlying issue as soon as possible. For high-severity errors, disconnect the appliance and contact a qualified technician. ### How much does it cost to fix error Er1 on a Siemens ? Repair costs for error Er1 on the Siemens range depend on the root cause. DIY fixes such as cleaning filters, resetting the unit, or reconnecting loose wires cost nothing beyond basic tools. If a component replacement is needed, parts and labor from a certified technician are the main expenses. Contact a Siemens-authorized service provider for an accurate estimate based on your specific situation. ### What does error code Er1 mean on a Siemens range? Error code Er1 on Siemens range models indicates Oven temperature sensor fault — PT5000 sensor disconnected or open circuit. This error is detected by the appliance’s internal diagnostic system and displayed to alert the user that attention is needed. Refer to the troubleshooting steps above for guidance on resolving this issue.