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Error code reference

Miele Dishwasher Error Code F88

Turbidity sensor fault; false or no values from turbidity sensor

Miele codesMiele dishwasher codes

Turbidity sensor fault; false or no values from turbidity sensor. Program continues with default settings. Only indicated in fault memory.

First step from the service manual

Check the turbidity sensor for correct function.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What F88 means on a Miele dishwasher

The F88 error code on a Miele dishwasher indicates a turbidity sensor fault, meaning the control board is receiving false readings or no signal at all from the turbidity sensor. The turbidity sensor is an optical component that measures how cloudy or particle-laden the wash water is during a cycle. Based on those readings, the dishwasher normally adjusts water temperature, wash duration, and rinse cycles to optimize cleaning performance and water efficiency. When the sensor fails to deliver valid data, the machine cannot make those adaptive adjustments.

When F88 is triggered, the dishwasher does not stop mid-cycle or lock out operation. Instead, it falls back to a fixed set of default program parameters and completes the wash as normal. This means dishes may still come out clean, but the machine is no longer optimizing its water and energy usage based on actual load conditions. The error is logged silently in the fault memory and is not displayed on the main panel during normal operation, so it is typically discovered only during a service diagnostic read-out.

The most likely causes include a physically contaminated or fouled sensor lens, a faulty sensor that has failed electrically, or a wiring issue between the sensor and the control board. Because the sensor is exposed to wash water, grease, and detergent residue over time, buildup on the optical lens is a very common cause of degraded or missing signal output. Diagnosis should begin with a visual inspection and cleaning of the turbidity sensor, followed by electrical continuity and function checks if cleaning does not resolve the stored fault.

Source: manufacturer service documentation.

Common causes of F88

  1. 01

    Contaminated or fouled sensor lens

    Wiring / connection

    Grease, detergent film, or mineral scale buildup on the turbidity sensor's optical lens can block the light path and cause the sensor to return no usable signal. Inspect the sensor lens and clean it carefully; this is the most common cause of F88.

  2. 02

    Faulty turbidity sensor

    Part replacement

    The sensor itself may have failed electrically or its optical emitter or receiver may have degraded over time. If cleaning the lens does not resolve the fault, the sensor should be tested for correct function and replaced if it is not operating within specification.

  3. 03

    Wiring or connector fault

    Wiring / connection

    A loose, corroded, or damaged connector between the turbidity sensor and the control board can interrupt the signal entirely, causing the board to log a sensor fault. Inspect the wiring harness and connector pins for corrosion, moisture damage, or poor contact.

  4. 04

    Control board failure

    Part replacement

    If the sensor and its wiring check out correctly, the control board itself may be failing to read the sensor circuit. This is a less common cause but should be considered after all other components have been ruled out.

See the test procedure for each cause

Frequently asked questions about F88

What does F88 mean on a Miele dishwasher?
F88 indicates a turbidity sensor fault, meaning the dishwasher received false or no readings from the sensor that monitors how dirty the wash water is during a cycle. The machine continues running using built-in default settings rather than adjusting automatically based on water clarity. This code is only stored in the internal fault memory and is not shown on the display during normal use.
Can I still use my Miele dishwasher when F88 is stored in the fault memory?
Yes, the dishwasher will continue to operate normally when F88 is logged. The machine simply runs on fixed default program settings instead of optimizing the cycle dynamically. However, you should have the sensor inspected and serviced to restore full adaptive functionality and efficiency.
Will resetting my Miele dishwasher clear the F88 fault code?
A reset may clear the fault from the active display, but if the underlying sensor problem has not been corrected, the fault will be logged again during the next cycle. The proper resolution is to diagnose and repair the turbidity sensor or its wiring before clearing the fault memory.
Is F88 a safety concern on a Miele dishwasher?
F88 is not a safety-related fault and does not indicate any risk of water leakage, electrical hazard, or damage to the appliance. The dishwasher is designed to continue running safely on default settings when this fault occurs. That said, leaving the fault unaddressed means the machine is not cleaning or using water as efficiently as it should.
How much does it cost to fix a Miele dishwasher F88 error?
Repair costs vary depending on the root cause. If the fault is caused by a dirty sensor lens, cleaning it costs nothing beyond a service call, which typically ranges from around 80 to 150 dollars. If the turbidity sensor itself needs replacement, parts and labor combined can range from approximately 150 to 350 dollars depending on your location and the technician's rates.

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