Bosch Refrigerator Error Code E08

Error code E08 on a Bosch refrigerator indicates that the sensor responsible for monitoring temperature in the chiller compartment vaporiser, wine storage compartment vaporiser, or chiller compartment vaporiser is reading a value outside the acceptable operating range. The vaporiser in each of these zones is a heat exchanger component where refrigerant evaporates and absorbs heat, and the associated NTC (negative temperature coefficient) thermistor sensor continuously feeds temperature data to the control board. When the sensor signal falls outside the predefined limits, either too high or too low in resistance or voltage, the board interprets this as a fault and logs E08.

The most common root cause is a failed or degraded NTC temperature sensor. NTC sensors change resistance in response to temperature, and when the sensor shorts, opens, or drifts out of calibration, the control board receives an implausible reading. Wiring issues between the sensor and the control board, such as corroded connectors, pinched wires, or loose terminals, can produce the same out-of-range signal without the sensor itself being defective. In some cases, ice buildup around the vaporiser can physically damage the sensor or its wiring harness.

Because the error covers multiple potential zones (chiller compartment or wine storage compartment), the first step in diagnosis is identifying which sensor circuit is affected. This typically involves measuring the resistance of each suspect NTC sensor at a known temperature and comparing it against the expected resistance curve. A properly functioning NTC sensor will show a predictable and smooth resistance change with temperature. An open circuit or a fixed resistance reading points clearly to sensor failure, while a reading that fluctuates erratically suggests a wiring or connector problem.