Bosch Washer Error Code 25

Error code 25 on a Bosch washer indicates that the Aqua Sensor, also called the turbidity sensor, has failed to calibrate its operating point. This sensor monitors water clarity to optimize wash and rinse cycles. The most common cause is limescale buildup on the sensor from hard water, though wiring issues or a failed sensor can also trigger this code.

A reset may temporarily clear the error code from the display, but it will return if the underlying cause is not addressed. The sensor calibration failure is tied to a physical condition, such as scale buildup or a hardware fault, that a reset cannot fix. The sensor or wiring issue must be resolved for the code to clear permanently.

If the repair is just a cleaning of the Aqua Sensor, costs are minimal, mainly your time or a small service call fee. If the turbidity sensor needs to be replaced, parts typically range from around 30 to 80 dollars depending on the model, with professional labor adding 80 to 150 dollars or more depending on your area. A full diagnosis by a technician will give you a more accurate estimate for your specific situation.

In some cases, yes. If the Aqua Sensor is coated in limescale, cleaning the sensor with a descaling solution may restore normal function. You should also check that the wire harness connected to the sensor is secure and undamaged. If cleaning does not resolve the fault, the sensor likely needs to be replaced, which requires some disassembly and comfort working with appliance wiring.

Error code 25 affects the washer's ability to monitor water turbidity and optimize its cycles, but it does not represent an immediate safety hazard. However, running the machine in a fault state can lead to inefficient washing or improper rinsing, and continuing to ignore the fault may stress other components over time. It is best to diagnose and repair the issue before regular use continues.