Bosch Dryer Error Code E:85

Error code E:85 on a Bosch dryer indicates a fault in the NTC (Negative Temperature Coefficient) thermistor associated with the refresher function. The refresher is a cycle mode that uses steam or gentle heat and tumbling to dewrinkle and freshen garments without a full wash cycle. The NTC thermistor in this circuit is a temperature-sensing resistor whose resistance decreases predictably as temperature rises. The dryer's control board monitors this resistance continuously, and when the readings fall outside the expected range, either too high, too low, or completely open/short circuit, the board logs E:85 and halts operation to prevent potential overheating or damage to garments.

The most common root cause is a failed NTC thermistor itself, which can drift out of specification or fail entirely due to heat cycling over time. Wiring issues are equally common: corroded terminals, a loose connector plug, or a damaged wire in the harness connecting the NTC to the control board can all produce erratic resistance readings that trigger this fault. In some cases, moisture intrusion into the connector can cause intermittent faults that appear and disappear between cycles.

Diagnosis begins with a resistance check of the refresher NTC using a multimeter. A correctly functioning NTC will show a specific resistance value at room temperature that decreases as heat is applied. If the thermistor reads open circuit, shorted (near zero ohms), or a value inconsistent with the expected temperature curve, the sensor must be replaced. All electrical connections in the NTC circuit should also be inspected for corrosion, looseness, or physical damage before condemning the sensor itself.