The short answer
The short reading of F25 on a Bosch washing machine: there is a problem with the turbidity sensor. The machine will generally still wash, using default rinsing rather than measured rinsing, so results are acceptable but less efficient. Most of what follows is diagnosis rather than repair, and the repair end of it is a technician job.
Error codes
Reference| Code | Meaning |
|---|---|
| F25 | These error codes indicate there is an issue with the turbidity sensor. |
What the machine does alongside the code
- The machine runs default rinses rather than adapting to the load — Without the measurement, the control falls back on a fixed programme.
- The fault moves when the appliance is knocked or something is set down hard on it — A vibration-sensitive fault is a connection fault, and that is half of what this code covers.
What triggers F25, most likely first
- Residue or scale clouding the sensor window — It goes first because it is the commonest and the cheapest: the sensor reads through a window in the water path, and detergent film or scale over that window makes its reading unusable.
- A chafed or broken conductor in the harness to the turbidity sensor — The run passes edges and hinges, and a conductor broken where it flexes gives the control the same silence a failed part gives it.
- A control board that no longer drives or reads that circuit — Last, deliberately: it is the most expensive candidate and it cannot be diagnosed at all until the three cheaper ones are cleared.
Check in this order, and why
- Run a maintenance wash with a machine cleaner and no load — This clears the film that clouds the sensor window and it is the one owner action that can fix the code.
- Have the turbidity sensor measured at the control connector — One measurement at the board end tests the part and its wiring together, which is exactly what the code covers.
- Note whether the wash still completes normally — A completing cycle with a sensing code is a different situation from a cycle that stops.
- Body: Pin the symptom to one function before opening anything — a single dead function and a general misbehaviour lead to completely different work.
The reset, then the owner-safe checks
- Run an empty maintenance wash at the highest temperature with a machine cleaner, then retest — Descaling and degreasing the circulation path is what clears a clouded sensor window.
About 90 min
- Use the appliance the same way again and note the exact moment the code lands — The trigger point is the most useful thing you can hand a technician, and it costs one session to get.
About 45 min
- Check the outside of the appliance for what moved — A recent move, a service visit or a panel that has been off puts a loose connector at the top of the list.
About 10 min
- STOP HERE — the turbidity sensor and its wiring are behind a panel — Everything past this point is work next to live terminals, which is where an owner check ends.
Before anything is opened
Safety
Switch the machine off at its breaker before removing a panel, and close the supply tap before disturbing a hose. Stored charge remains after the power is off, water and live terminals share one cabinet, and the door interlock is never to be bypassed.
When this is a service call rather than a reset
Call once the code survives a power cycle, because everything remaining is behind a panel: inspecting the harness where it flexes, reseating the connectors at both ends, and measuring the circuit at the control.
Neighbouring codes on Bosch washing machines
What this page does not cover
This reading applies to the Bosch washing machine line as a whole, not to one family or model. It does not cover what differs between model lines — wiring colours, connector positions, part numbers and service-mode sequences — which are in your own model manual and which a technician matches to the rating plate rather than to this code. Where a family- or model-specific page for this code exists, it is linked from the code index below and it is the more specific answer.
Links: - [Bosch washing machine error codes](/blog/bosch-washer-error-codes)
Where to go next
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
