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Error code reference

Bosch Washer Error Code 23

Aqua stop actuated

Bosch codesBosch washer codes

Aqua stop actuated - water in the base tub, leaky water system, aqua stop switch blocked or 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 23 means on a Bosch washer

Error code 23 on a Bosch washer indicates that the Aqua Stop system has been activated due to the detection of water in the base pan of the machine. The Aqua Stop system is a leak protection mechanism that includes a float switch mounted in the bottom tray of the appliance. When water accumulates in the base pan, the float rises and triggers the switch, which signals the control board to halt operation and display error code 23. This is a safety-driven shutdown, not a malfunction of the Aqua Stop system itself, though the switch can also be the source of the fault.

The root cause of error 23 is typically an active leak somewhere within the water-carrying circuit of the washer. Common leak sources include the door boot seal, hose connections at the inlet valve or pump, the drum bearings seal, the detergent drawer housing, or the pressure hose connecting the pressure chamber to the water level sensor. Any of these components can allow water to drip or flow into the base pan over time, eventually raising the float and triggering the shutdown.

In some cases, the Aqua Stop switch itself may be the problem rather than an actual leak. A mechanically stuck float, a float switch with a broken contact, or damaged wiring in the harness connecting the switch to the control board can all cause a false positive activation of error 23. Diagnostics should address both possibilities: confirming whether water is actually present in the base pan and verifying the electrical integrity of the switch and its wiring.

Source: manufacturer service documentation.

Common causes of 23

  1. 01

    Active water leak in the plumbing circuit

    Part replacement

    Leaking hose connections, a faulty inlet valve, a damaged pump seal, or a deteriorated door boot seal can allow water to drip into the base pan over time. Inspect all water-carrying components for moisture, staining, or visible drips.

  2. 02

    Failed or torn door boot seal

    Part replacement

    The rubber gasket between the door and the drum can crack or tear, allowing water to escape during the wash or spin cycle and collect in the base pan. Look for visible damage or water marks around the door opening.

  3. 03

    Aqua Stop float switch stuck or faulty

    Part replacement

    If the float in the base pan is mechanically stuck in the raised position, or if the switch contacts are broken or corroded, the control board receives a constant fault signal even when no water is present. Check the switch for free movement and test continuity across its terminals.

  4. 04

    Damaged or disconnected wire harness

    Wiring / connection

    A broken, pinched, or corroded wire in the harness connecting the Aqua Stop float switch to the control board can trigger a false error 23 reading. Inspect the wiring for visible damage and confirm secure connections at both ends.

  5. 05

    Leaking detergent drawer or housing

    Wiring / connection

    A clogged or cracked detergent drawer housing can cause water to overflow internally and drip into the base pan. Remove and inspect the drawer housing for blockages or cracks, particularly around the water inlet nozzles.

See the test procedure for each cause

Frequently asked questions about 23

What does 23 mean on a Bosch washer?
Error code 23 means the Aqua Stop leak protection system has been triggered by water collecting in the base pan of the washer. The float switch in the bottom tray has risen and signaled the control board to shut the machine down. This could indicate a real leak in the water system, a stuck float, or a fault in the switch wiring. The washer will not resume operation until the underlying issue is resolved and the base pan is cleared of water.
How do I fix error code 23 on my Bosch washer?
Start by tilting the machine slightly forward to allow any water in the base pan to drain out, then inspect all internal hoses, the door boot seal, the pump, and the inlet valve for signs of leaking. Check the Aqua Stop float switch for mechanical freedom and verify continuity in its wiring harness. Once the leak source is repaired or the faulty switch is replaced, the error should clear on restart.
Is it safe to use my Bosch washer while error 23 is showing?
No, you should not attempt to run the washer while error 23 is active. The machine has shut down specifically to prevent water damage to the electrical components in the base of the unit. Running it in this condition risks electrical hazards and further damage. Address the leak or switch fault before resuming use.
Will resetting my Bosch washer clear error code 23?
A basic power reset will not permanently clear error 23 if the underlying fault is still present. The Aqua Stop float switch will continue to signal a fault as long as water remains in the base pan or the switch is defective. You must remove the water from the base tray and repair the root cause before the error will stay cleared after a reset.
How much does it cost to repair a Bosch washer showing error 23?
Repair costs vary depending on the root cause. Replacing a door boot seal typically runs in the range of $100 to $200 including parts and labor, while a new inlet valve or pump seal repair may cost between $150 and $300. If the Aqua Stop float switch itself is the only faulty component, the fix is generally on the lower end of that range. Wiring harness issues may fall anywhere depending on the extent of the damage.

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