Bosch Range Error Code E204

Error code E204 on a Bosch range indicates that the temperature sensor for Cavity 2, which is the warming drawer, has shorted to ground. A temperature sensor short to ground means the signal wire or the sensor element itself is making unintended electrical contact with a grounded metal surface, causing the control module to read an abnormal voltage level on that circuit. Because the control cannot obtain a valid temperature reading, it responds by shutting down all heating in the warming drawer and simultaneously running the cooling fan at maximum speed to protect surrounding components from potential heat buildup.

The temperature sensor in the warming drawer is a resistive device, meaning its electrical resistance changes predictably with temperature. Under normal conditions, the control module monitors the voltage across this sensor to calculate cavity temperature. When a short to ground occurs, the measured resistance drops dramatically or reads near zero ohms, which falls outside any valid operating range. This condition is distinct from an open circuit fault and points specifically to an unwanted low-resistance path between the sensor circuit and chassis ground.

Diagnosing E204 requires a two-step approach. First, visually inspect the wiring harness running to the warming drawer sensor for any pinched, chafed, or burned wires that could be contacting the metal chassis or frame. Second, disconnect the sensor and measure its resistance directly with a multimeter. If the sensor resistance reads within its normal specification for the current ambient temperature and the wiring harness checks out clean, the control module itself may be misreading the signal and could be the source of the fault. If the sensor reads near zero ohms or shows a direct short, the sensor requires replacement.