Bosch · Washing Machine
Bosch Washing Machine E23 Error Code
AquaStop detected water in the base pan
What this error means
E23 (F23 on some models) means the AquaStop float in the sealed base pan detected water. Bosch cuts inlet valves and locks the display to prevent floor flooding from a hose, tub seal, or suds overflow.
How E23 is detected
When E23 appears on a Bosch washing machine, the control board has confirmed that water did not leave the machine within the programmed drain window. On Bosch WAW285H1UC, Bosch WAT28400UC, and similar variants, the drain pump runs for a fixed interval—often three to seven minutes on washers and dishwashers—while a pressure switch or turbidity sensor verifies the tub or sump is empty. If water remains, the cycle stops to prevent spin with a full tub or overflow on the next fill.
Most E23 calls are resolved without parts: turn off hot and cold supply taps behind the washer immediately. Restricted drain paths mimic pump failure because the impeller spins against a blocked hose or filter. Document whether the pump hums audibly during the drain step; a humming pump with no water movement points to a clogged filter or kinked hose, while silence may indicate a failed pump motor or loose wiring at the harness.
After clearing blockages, run a short cycle and listen at the drain hose for steady water flow. If E23 returns on the next load with a clean filter and straight hose, measure resistance at the pump motor connector per the service manual for your model before ordering a replacement pump assembly.
Common causes
- Loose fill hose connection weeping at the rear valve block
- Door boot tear along the bottom fold spraying during high spin
- Overdosed detergent creating suds that escape the door gasket
- Internal tub-to-pump hose clamp slipped off inside the cabinet
Step-by-step fixes
- 1Turn off hot and cold supply taps behind the washer immediately
- 2Unplug the machine and tilt forward slightly to inspect the base tray with a flashlight
- 3Soak up water until the float drops—E23 may clear after the pan is dry
- 4Run one short cycle while watching under the machine for a new leak path
When to call a technician
If AquaStop trips again after one dry cycle, an internal hose or tub seal inside the cabinet is leaking and needs professional access.
Affected models
- Bosch WAW285H1UC
- Bosch WAT28400UC
- Bosch WGB246AXUC
Prevention & maintenance
- Clean drain filters and hose terminations monthly on high-use washing machines to prevent E23 from lint and food debris buildup.
- Record when E23 appears in the cycle and whether it clears after a 60-second power reset on your Bosch washing machine—that detail speeds diagnosis if you call service.
- Keep the model and serial number from the rating plate when ordering parts for E23; Bosch uses multiple revisions with different harness lengths and board firmware.
- Photograph wiring connector orientation before disconnecting any component while troubleshooting E23; reversed plugs on pumps and valves cause immediate repeat faults.