If the door of a Bosch WAT28400UC will not open, Bosch's troubleshooting table lists the reasons: the Child lock is activated (touch and hold Temperature and Finish in for about 3 seconds to deactivate it), a power failure occurred, the cycle is still running, the water level is too high or too hot, or the emergency door lock release was activated. The door is locked for safety reasons when the water level is high, the water temperature is hot or the drum speed is high. If the door still cannot be opened after turning the washer off and back on, use the emergency door lock release, after the water has cooled and been drained.
Differential
Likely causes of “Bosch 300 Series WAT28400 front-load washer door or lid will not unlock”, and how to tell them apart
- 1
The Child lock is on
What separates it The D symbol is lit and the door will not open
How to confirm Touch and hold Temperature and Finish in for about 3 seconds
- 2
The cycle is running or the water is hot
What separates it The door is locked for safety because the cycle is running or the water is hot
How to confirm Wait until the cycle ends and the water cools
- 3
A power failure
What separates it The door stays locked after an outage because of a power failure
How to confirm A cycle interrupted by a power failure resumes when power returns; wait
- 4
A blocked drain leaving water in the drum
What separates it The door will not open with water visible because a blocked drain leaves water in the drum
How to confirm Drain the water using the pump maintenance steps first
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether the D symbol is lit
- Whether water is visible through the glass
- Whether a power failure happened lately
Try in this order
0 of 5 completedCheck the Child lock
ReversibleIf D is lit, touch and hold Temperature and Finish in for about 3 seconds.
Wait for the cycle
ReversibleWait for the cycle, since the door stays locked while the drum turns, or the water is high or hot.
Turn the selector off and on
ReversibleTurn the selector off and on, since this cancels any running program and may release the door.
Drain the water
ReversibleDrain the water, and if water is visible, follow the drain pump steps before opening the door.
Use the emergency release
ReversibleTurn the washer off, unplug it, let the water cool, drain it, remove the service cover screws and protective foil and pull the release rod down with a tool.
Model-specific
What is true of this model and not of its siblings
- Emergency door lock release, in order
- Turn the washer off with the cycle selector at Off, which cancels the running program, and disconnect the plug. Let the water in the drum cool and let the drum stop. Perform the drain procedure in the pump maintenance section. Loosen the screws and remove the protective foil, pull the emergency release downwards with a tool and release it, and the door can then be opened.
- Child lock behavior
- The Child lock can remain activated until the next cycle start even after switching the machine off, and you must deactivate it before you can set a cycle. It secures the washer against inadvertent changes of the set functions and is activated after cycle start. A washer that seems to ignore the selector and buttons may simply have the Child lock on.
- Parts for this problem on the WAT28400 (RepairClinic, 2026-09-20)
- pressure sensor, part number 10009438, at $43.31; door boot seal, part number 20007273, at $90.56.
- Other models this page answers
- These steps also fit the 300 Series WGA12400UC washer, 800 Series WAW285H2UC washer, 800 Series WGB24600UC washer.
Stop boundary
When this stops being a self-service repair
- !If the door still will not open after turning the washer off and on, use the emergency release as the manual describes, or call Bosch service
- !If the release rod does not work, stop and call service
Evidence ledger
Sources behind this answer
Bosch's own US owner-support pages for washer error codes and self-help.
Parts and list prices as shown on RepairClinic's parts search for this model number on 2026-09-20.
Exact questions
Common questions
Why won't my Bosch door open?+
The Child lock is on, the cycle is running, water is high or hot, or power failed.
What does the D symbol mean?+
The D symbol means that the Child lock is active.
What does a blinking D mean?+
The Child lock is active and the cycle selector was adjusted; set it back to the initial cycle.
Will the cycle resume after a power cut?+
Yes; the program continues when power is restored.
Where is the emergency release?+
Behind the service cover at the bottom front, a rod pulled downwards with a tool.
Is it safe to open a door with water inside?+
No, it is not safe to open a door with water inside, so drain it and let it cool first.
Are the transport bolts removed?+
They must be removed at installation, or the washer will shake and make a violent noise.
What is the largest cotton load?+
Regular cotton loads go up to 15.4 lb, which is 7 kg.