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Error code reference

Bosch Washer Error Code F:23

Aqua stop actuated

Bosch codesBosch washer codes

Aqua stop actuated - water in the base tub, leaky water system, or aqua stop switch is blocked/broken.

First step from the service manual

Check leak tightness of water system, check aqua stop switch, check wire harness.

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

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What F:23 means on a Bosch washer

The F:23 error code on a Bosch washer indicates that the Aqua Stop system has been actuated, meaning the machine has detected water in the base pan beneath the drum assembly. The Aqua Stop system is a flood prevention mechanism that uses a float switch mounted in the base tray. When water accumulates in this tray, the float rises and triggers the switch, which signals the control board to halt operation and shut off the water inlet valve. This is a safety-critical function designed to prevent water damage to your home.

The most common reason this code appears is an actual water leak somewhere in the system. Leak sources can include the door boot seal, hose connections at the pump or drum, the drain hose, the inlet valve assembly, or the detergent dispenser housing. Even a slow, intermittent drip over time can accumulate enough water in the base pan to actuate the float switch. The leak must be identified and repaired before the machine will return to normal operation.

Beyond an active leak, the code can also be triggered by a faulty or stuck Aqua Stop float switch that activates without actual water present. Corrosion, debris, or mechanical failure can cause the switch to report a fault incorrectly. The wire harness connecting the float switch to the control board should also be inspected for damaged insulation, loose connectors, or broken wires, any of which can send a false trigger signal to the control module.

Source: manufacturer service documentation.

Common causes of F:23

  1. 01

    Active water leak in the system

    Part replacement

    A leak from the door boot seal, internal hoses, pump connections, or inlet valve allows water to drip into the base pan and trigger the float switch. Inspect all water-carrying components for visible moisture, mineral deposits, or drip trails.

  2. 02

    Water accumulated in base pan

    Wiring / connection

    Even if the leak has since stopped or been fixed, residual water sitting in the base tray will keep the float switch actuated. The base pan must be dried out completely before the code will clear.

  3. 03

    Faulty or stuck Aqua Stop float switch

    Part replacement

    The float switch in the base pan can become stuck in the triggered position due to debris, corrosion, or mechanical wear, causing a false F:23 fault with no actual water present. Check that the float moves freely and that the switch tests correctly for continuity.

  4. 04

    Damaged or disconnected wire harness

    Wiring / connection

    A broken wire, corroded connector, or damaged harness between the float switch and the control board can send a false fault signal. Inspect the full length of the wiring from the base pan switch to the control module for visible damage or loose terminals.

  5. 05

    Leaking detergent dispenser or overflow

    Part replacement

    Excessive detergent use or a cracked dispenser housing can cause water to overflow and run down into the base pan rather than into the drum. Check the dispenser drawer and its housing for cracks and ensure the correct detergent type and quantity is being used.

See the test procedure for each cause

Frequently asked questions about F:23

What does F:23 mean on a Bosch washer?
F:23 means the Bosch washer's Aqua Stop flood protection system has been triggered by water detected in the base pan beneath the machine. A float switch in the base tray rises when water is present and signals the control board to stop operation. This is typically caused by an internal water leak, though a faulty switch or wiring issue can also produce this code. The washer will not run again until the root cause is resolved and the base pan is dry.
Can I fix the F:23 error myself?
Some steps can be handled without a technician, such as drying out the base pan, inspecting visible hose connections for leaks, and checking the float switch for debris or obstruction. However, if the source is a torn door boot seal, a cracked internal hose, or a failed component like the inlet valve or pump, replacement parts and moderate disassembly skills will be required. If you are not comfortable working inside the appliance, a qualified repair technician is recommended.
Is it safe to use my Bosch washer when F:23 is showing?
No, you should not attempt to run the washer while F:23 is active. The error indicates water is or was present in the base of the machine, which poses a risk of further water damage to your home and potential electrical hazards. The Aqua Stop system is specifically designed to halt operation in this situation, and bypassing it is not advised.
Will resetting the washer clear the F:23 code?
A simple power reset will not permanently clear F:23 if water remains in the base pan or if the underlying leak or component fault has not been fixed. The float switch will continue to signal a fault as long as it is actuated. You must first address the cause, dry out the base tray completely, and confirm the float switch is seated and moving freely before the code will clear on its own.
How much does it cost to repair a Bosch washer showing F:23?
Repair costs vary depending on the root cause. If the fix involves only drying the base pan and tightening a loose hose connection, the cost may be minimal. Replacing a door boot seal typically falls in the range of $100 to $250 including parts and labor. A failed pump, inlet valve, or Aqua Stop switch assembly with professional installation could run $150 to $400 or more depending on parts pricing and local labor rates.

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