If the Bosch WAT28400UC will not start because of the door, the error message table gives the answer: a flashing door symbol means the door is not closed properly, so check that no laundry is caught in the washer door and close the door securely until a click is heard, after which the cycle should start. Bosch's General Troubleshooting says the same for a cycle that does not start: check if laundry is caught in the door and close the door until a click is heard. The door has a magnetic lock and opens 160 degrees, and it will not lock if the emergency release has been activated.
Differential
Likely causes of “Bosch 300 Series WAT28400 front-load washer will not start because”, and how to tell them apart
- 1
Laundry caught in the door
What separates it The door symbol flashes and Start does nothing because laundry is caught in the door
How to confirm Check nothing is caught and close the door until it clicks
- 2
The door not closed firmly
What separates it No click is heard because the door is not closed firmly
How to confirm Push the door until the magnetic lock clicks
- 3
The emergency door lock release is activated
What separates it The door will not lock or the cycle will not start
How to confirm Reset the release rod and close the door
- 4
Child lock is activated
What separates it Settings cannot be changed and the cycle will not start
How to confirm Touch and hold Temperature and Finish in for about 3 seconds
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether the door symbol flashes on the display
- Whether a click is heard on closing
- Whether Child lock is switched on
Try in this order
0 of 5 completedCheck the door
ReversibleCheck the door, and make sure that no laundry is caught and close it until a click is heard.
Touch Start/Pause
ReversibleTouch Start or Pause, and the cycle should start once the door is latched, and then test again to see whether it helped.
Check the emergency release
ReversibleCheck the emergency release, since if it was activated, the door will not lock, so reset it.
Check Child lock
ReversibleCheck Child lock, since D lit means that it is on, and then test again to see whether it helped.
Call service
ReversibleCall service, and if the flashing persists, call with the E-Nr. and the FD number.
Model-specific
What is true of this model and not of its siblings
- Where the identification plate is
- Bosch asks for the E-Nr. (model number) and the FD (serial) number when you contact customer service, and says the identification plate carries them inside the appliance door or on the back of the appliance. Give those numbers with the display symbol you see, since the door and lock messages differ between Bosch washer lines.
- Start/Pause and other start problems
- Bosch lists other reasons a cycle does not start: Start/Pause flashing because the button was not touched, a Finish in time displayed because a delayed finish is set, and a D symbol flashing because the Child lock is on. Each has its own fix, so read which symbol the display shows before assuming a door fault.
- 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 symbol flashes with the door clearly closed and clear, call Bosch customer service on 1-800-944-2904
- !If the door glass or hinge is damaged, stop using the washer
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 does my Bosch door symbol flash?+
The door is not closed properly; check for laundry caught and close it until it clicks.
How wide does the door open?+
160 degrees with a magnetic lock, per Bosch's manual.
What are the E-Nr. and FD numbers?+
The model and serial numbers on the identification plate inside the door or on the back.
Can the emergency release stop it locking?+
Yes; if it is activated the door will not lock.
Does Child lock affect the door?+
It can prevent the settings being changed and the door opening mid-cycle.
How do I clean the dispenser tray?+
Press down the drawer catch, pull the tray out, and rinse the tray and the insert under warm running water.