Bosch Refrigerator Error Code F51

F51 indicates that the finger protection sensor system recorded a reference measurement that was too high during its dark-state baseline check, meaning the photodetector detected significant light even though no LED in the circuit should have been lit. This can be caused by external ambient light reaching the sensor or by an LED that is failing to turn off. The error prevents the finger protection system from functioning reliably, so the refrigerator flags it immediately for diagnosis.

The finger protection system is a safety feature designed to detect obstructions near moving components and prevent injury. When F51 is active, this system cannot perform accurate measurements, which means the safety monitoring is compromised. It is advisable to address the error promptly rather than continuing to operate the appliance with a non-functional safety circuit.

A power reset may temporarily clear the F51 code, but if the underlying cause such as excessive ambient light or a failed LED or sensor component is still present, the error will return. A reset alone is not a fix and should be used only as part of diagnosing whether the fault is intermittent. Resolving the root cause is necessary to prevent the code from recurring.

Start by checking whether bright ambient light is reaching the finger protection sensor area, and reduce or block that light source to see if the code clears. Next, visually inspect the sensor zone to confirm no LED is visibly illuminated when it should be off. If environmental factors are not the cause, the sensor assembly, associated wiring, or the control board may need to be inspected and potentially replaced by a qualified technician.

If the cause is simply external light interference, there may be no parts cost at all. If a sensor assembly replacement is needed, parts and labor typically range from around 100 to 300 dollars depending on the specific model and local labor rates. A control board replacement, if required, can range from 200 to 500 dollars or more including labor.