Bosch washers show codes as E or F followed by a number, and the two letters mean the same thing: E16 is an open door, E17 a water-supply timeout, E18 a blocked pump, filter or hose, E19 and E20 heater faults, E23 means the AquaStop leak protection has triggered, and E25 and E26 are sensor faults. Bosch publishes only a short list; this guide covers just those codes, without guessing at others.
Codes Bosch publishes
| Code (E or F) | Bosch’s description |
|---|---|
| E16 / F16 | Door is open |
| E17 / F17 | Water supply time exceeded |
| E18 / F18 | Blockage in the filter or pump, or a blocked or kinked hose |
| E19 / F19 | Heating time exceeded |
| E20 / F20 | Unexpected heating |
| E23 / F23 | AquaStop hose has been activated |
| E25 / F25 | Turbidity sensor issue |
| E26 / F26 | Analogue pressure sensor issue |
| F27 | Faulty pressure sensor |
| E28 / F28 | Flow sensor issue |
| E56 | Unexpected communication error |
E16: Door
Bosch’s advice for E16 or F16 is to close the door and continue as usual; if the error stays after the door is shut, check it is closed fully and nothing, such as a sock, is caught in the seal. If the door will not open at the end of a cycle, see washing machine door will not open.
E17 and E18: Water supply and drainage
- E17: check the supply side
Bosch describes E17 as the water-supply time being exceeded, and for this code its US page refers owners to customer support. Before calling, confirm the tap is fully open and the inlet hose is not kinked.
- E18: clean the pump
Bosch says E18 appears when it detects a blockage in the filter, or a blockage or kink in the hose. Its steps: switch the machine off, open the service flap, drain the water, clean the pump and impeller, and test with a liter of water in the drawer.
- E18: check the drain hose
Make sure the drain hose is installed without kinks and the siphon connection is clean.
See our detailed Bosch washer E18 guide and the general won’t drain guide.
E23: AquaStop activated
E23 or F23 means the AquaStop leak-protection system has activated, which suggests water leakage. Bosch’s instructions are to turn off the water tap immediately, stop using the machine, and arrange a service appointment — the fault cannot be rectified by the owner. Mop up any water around the machine first.
E19 and E20: Heating
E19 (heating time exceeded) cannot be rectified by the owner, according to Bosch. E20 reports unexpected heating, which is a safety-relevant fault. In both cases, stop using the hot cycles and request service. A washer that fills and washes but does not warm the water is a heater or thermostat issue.
Sensor and communication codes
E25, E26, F27 and E28 (turbidity, pressure and flow sensors) and E56 (communication) all point to parts inside the machine. Bosch lists them as service items; there is no owner fix. If you see several different codes in a short time, power the machine off for a minute and restart it once — but a returning code needs a technician.
A code that is not listed
If your washer shows a code that is not in the table, Bosch’s guidance is to contact Bosch Customer Support. You will find some older F-codes discussed elsewhere (for example F21 and the motor), but they are not in Bosch’s published list, so treat any such advice with caution. For Bosch dryers see Bosch dryer error codes.
When to call for service
E17 (if the tap and hose are fine), E19, E20, E23 and every sensor or communication code need service. Check the likely cost against replacement with our washing machine repair cost guide.
