What E204 Means
E204 is the lower-cavity temperature sensor shorted to ground on a Bosch double wall oven. The oven's response mirrors the upper-cavity version: heating in that cavity stops and its cooling fan goes to high speed until two consecutive good readings come through. Bosch's action list starts with checking the wiring for pinching or a short to metalwork rather than with the sensor itself.
Common Causes of E204
- Lower cavity sensor wiring shorted against chassis or cavity metal
- Sensor probe internally shorted
- Harness insulation damaged by heat behind the lower cavity
🔧 One Safe Check You Can Try
Nothing here is a home check beyond confirming which cavity misbehaves. Run a short bake in the upper oven and then the lower one and note which fails, because that is what distinguishes this code from its upper-cavity twin.
⚠ Why You Shouldn't Go Further Than That
- Harness routing behind a stacked double oven is tighter than on a single appliance, which is precisely why pinched wiring is the first thing Bosch tells technicians to look for.
- Both cavities feed one control module, so a short on one circuit can present symptoms that seem to involve the other.
- A double wall oven is heavy and awkward to draw out of a cabinet, and doing it alone risks both the appliance and the person.
- Resistance readings decide between a sensor and the shared control module, and getting that wrong is an expensive mistake on a double oven.
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.