Bosch Washer F23 Error Code — What It Means
F23 on Bosch washers means the AquaStop or leak protection system has been activated. The machine has detected water in the base pan and has shut down to prevent flooding. Bosch’s official support page states this is an AquaStop activation fault, not a simple drain problem. A float or sensor in the bottom of the cabinet has lifted due to water collecting where it should not be. The machine will not run normally until you find and fix the leak and dry out the base pan. Some service articles describe F23 as a drain fault, but Bosch’s manufacturer guidance treats it as a leak detection event that requires servicing rather than a quick reset.
Common Causes
- Water leak inside the cabinet A leak from inlet hoses, hose connections, the detergent dispenser path, or internal plumbing drips into the base pan and triggers the AquaStop float.
- Faulty door gasket or boot Water escapes past a torn or improperly seated door seal during the wash cycle and runs down into the base.
- Leaking drain pump housing or internal hoses Cracked pump seals, loose clamps, or split internal hoses allow water to escape into the lower cabinet.
- Detergent drawer or dispenser leak Cracks, blockages, or overflow in the dispenser assembly send water down the front panel into the base pan.
- Defective AquaStop sensor or contaminated float The leak detection float or sensor itself is stuck, corroded, or malfunctioning and falsely signals a leak condition.
- Drain pump blockage (alternative interpretation) If your model uses F23 for drain faults, a clogged pump filter, kinked drain hose, or failed pump impeller prevents proper drainage and triggers the code.
Step-by-Step Fix
- Unplug the washer and turn off the hot and cold water supply valves before you begin any inspection or repair work.
- Pull the machine forward and tilt it slightly or remove the lower access panel to inspect the base pan for standing water, then soak up any water with towels and dry the pan completely.
- Check all inlet hoses and their connections at the back of the machine for cracks, loose fittings, or visible water trails, and tighten or replace any suspect hoses.
- Inspect the detergent dispenser drawer and surrounding housing for cracks, residue, or signs of overflow, and clean out any blockages or replace the drawer assembly if damaged.
- Examine the door gasket for tears, foreign objects, or improper seating, and verify that water is not escaping past the boot during a test cycle.
- Locate and clean the drain pump filter (usually behind a lower front panel) and inspect the drain hose for kinks, clogs, or damage, then test the pump by running a short drain cycle if no leak is found.
- Reset the AquaStop sensor by ensuring the base pan is dry and the float moves freely, then plug in the washer and run a test cycle to confirm the fault is cleared.
Parts Often Needed
| Part | Notes |
|---|---|
| Bosch washer inlet hose | Amazon | Replace if cracked or leaking at connections; make sure the new hose includes a built-in AquaStop valve if your model requires it. |
| Door boot gasket / door seal | Amazon | Match the part number to your exact Bosch model; tears or poor fit will cause leaks into the base pan. |
| Drain pump assembly | Amazon | Required if the pump housing is cracked or the impeller is jammed and the code is being used in a drainage-fault context. |
| AquaStop leak sensor / float switch | Amazon | Replace if the sensor is stuck or falsely triggering; often part of the base pan assembly on Bosch washers. |
When to Call a Pro
Bosch’s official support page states that F23 cannot be rectified by the user and requires service. If you have dried the base pan and inspected all visible hoses and connections but the code returns immediately or you cannot locate the source of the leak, call a qualified appliance technician. Internal leaks from the tub seal, pump housing, or pressure system often require cabinet disassembly and specialized tools. If the AquaStop sensor itself is defective or the leak is coming from inside the outer tub, professional diagnosis and parts replacement will save you time and prevent further water damage to your floor or cabinetry.