What E104 Means
E104 is the short-circuit counterpart to the open-sensor fault: the cavity temperature sensor circuit is shorted to ground. Bosch's suggested action names the likely mechanism, wires pinched or shorted against metalwork, before the sensor itself. The oven responds the same way it does to an open sensor, running the cooling fan at high speed and stopping heating until two good readings come through.
Common Causes of E104
- Sensor wiring pinched against the cavity or chassis
- Temperature sensor internally shorted
- Insulation damage on the sensor harness from heat
🔧 One Safe Check You Can Try
A breaker reset will tell you whether the short is constant or intermittent, and that is genuinely useful information. Anything beyond that means tracing wiring behind a built-in oven, which is not a home job.
⚠ Why You Shouldn't Go Further Than That
- Bosch puts pinched wiring ahead of a failed sensor in its own list, so the first thing to look for is damage caused by a previous reassembly.
- A short to the chassis on a circuit that runs through a heated cavity is worth tracing properly rather than working around.
- Resistance measurements here decide between a sensor and a control module, and reading them wrong costs the difference between the two.
- The harness routes near the broil element, where handling it carelessly can disturb the insulation that keeps the cabinet cool.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.