Gaggenau Oven Error Code E104

Error code E104 on a Gaggenau oven indicates a short-circuit condition in the PT1000 cooking compartment temperature sensor designated as sensor 1. A PT1000 is a platinum resistance temperature detector with a nominal resistance of 1000 ohms at 0 degrees Celsius. When the oven's control board detects that the resistance reading from this sensor has dropped to an abnormally low value consistent with a short circuit, it interprets this as a sensor fault and immediately triggers a protective response. All heating elements are switched off to prevent uncontrolled temperature conditions, and the cooling fan is driven at maximum speed to dissipate any residual heat in the cavity and electronics.

The PT1000 sensor monitors the cooking compartment temperature and feeds real-time resistance data to the control board, which converts that reading into a temperature value used to regulate all heating functions. A short circuit in this sensor circuit can result from a damaged or pinched sensor cable, corroded or loose connections at plug X20, moisture intrusion into the connector, or physical damage to the sensor element itself. The fault is not in the heating elements or control board but specifically in this measurement circuit, which is why the diagnostic process begins at the sensor connection and wiring before condemning the sensor.

To diagnose E104, start by inspecting the plug-in connection at plug X20, checking for corrosion, bent pins, or loose seating. Next, measure the resistance of the PT1000 sensor directly. A correctly functioning PT1000 should read approximately 1000 ohms at room temperature, with resistance rising proportionally as temperature increases. A shorted sensor will show near-zero ohms. If wiring and connectors check out and the sensor resistance reading is incorrect, the sensor itself must be replaced to clear the fault.