Gaggenau Oven Error Code F18

F18 on a Gaggenau oven means the PT 1000 temperature sensor in the lower oven cavity has been detected as having a short circuit. The PT 1000 is a platinum resistance sensor that monitors oven temperature, and a short circuit causes it to send an invalid signal to the control board. The oven disables heating operations when this fault is active to prevent uncontrolled temperatures. Diagnosis involves measuring the sensor's resistance and inspecting the associated wiring harness.

You should not attempt to use the oven while F18 is active. The error indicates the temperature monitoring system for the lower oven cavity is compromised, which means the oven cannot reliably regulate heat. Continued use without a functioning sensor could result in overheating or unpredictable temperature behavior. Discontinue use until the sensor circuit has been repaired.

Repair costs depend on which component has failed. A replacement PT 1000 oven temperature sensor typically costs in the range of $30 to $80 for the part alone. If a section of wiring harness or a connector needs replacement, parts costs are generally lower, but labor time increases. Professional service labor for a Gaggenau appliance can range from $100 to $250 or more depending on your region and the extent of the repair.

A technically experienced DIYer can diagnose the F18 error by using a multimeter to measure resistance across the PT 1000 sensor terminals at room temperature, looking for a reading close to 1000 ohms. If the sensor reads near zero ohms, it has failed and will need to be replaced. However, accessing the sensor may require partial disassembly of the oven cavity, and working around oven wiring carries electrical safety risks, so professional service is recommended if you are not comfortable with those tasks.

A power reset, such as switching off the circuit breaker for a few minutes and restoring power, may temporarily clear the F18 code from the display. However, if the PT 1000 sensor or its wiring has a genuine short circuit, the fault will return as soon as the control board re-evaluates the sensor circuit. Clearing the code without repairing the underlying cause does not restore safe oven operation.