The door locks when the start button is pressed, but the cycle will not start. Diagnostics shows F26 door lock assembly. Whirlpool WFW8300SW. I have replaced the CCU and it still locks but nothing happens after that.

Unplug for a few minutes and plug back in.


What happens when you run diagnostics?

DIAGNOSTIC TEST
The control must be in the OFF state before pressing the touch-pad sequence to start the test.
Starting the test mode

• Close the door.
• Press the Control On button.
• Select the DRAIN/SPIN cycle.
• Select NO SPIN by pressing the SPIN SELECT button, as needed.
• Push Prewash Option button four (4) times within five (5) seconds.
• C:00 will show in the display.
• NOTE: If Model does not have PREWASH Mode as an option, press RINSE/HOLD.
• If the Starting procedure fails, push PAUSE/CANCEL button. Then repeat the starting sequence.

Test Program Control during Execution To advance to the next step of the test procedure, push Prewash Option button two (2) times.

If the door lock is not engaging the control will not allow a cycle to start as a safety precaution, so the door lock assembly will need to be replaced if the door will not lock. You can order the new door lock assembly from the link below Genuine 8182634 Whirlpool Washer Door Switch Assembly eBay

C:00 is the beginning of diagnostics cycle need to let it finished. It will chime when completed

The error F26 does indicate a fault in the door switch circuit. See the image below for a complete listing of what can cause this error. There is a door unlock error that would display if the door is not locking or unlocking but the F26 means the control is not seeing the door switch open and close. One thing to try first before scheduling service or replacing the part is to check the connections on the door switch.
Unplug the washer first and remove the lower access panel and reach up to the door lock and try to feel for the connections and make sure they're tight.

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Here is the code meaning
F26 is for door lock - do you hear the door lock one time or with click sound repeatedly.
F20 no water entering - do you check water coming into washer
F21 long drain-do you take a look of pump filter
Another possibility is the pressure switch was bad.
Hope you can figure out the issue.

Suggestion: Unplug washer from mains. Open up the machine, disconnect and refit all connectors with wires one by one. Could be some loose connection somewhere. Also helps in the long run

Click if helped.

For the F28 error code:
First, check the wiring harness connections to the MCU, the Motor, and the CCU. Make sure all the connections are tight and there are no ground wires off. Then check the connections of the CCU board within the housing.

If the wiring connections are fine then It would be a good idea to order both, as both components have been problematic for the error code F28.
Here is a link to the CCU.
Here is a link to the MCU.

DOOR SWITCH ERROR

If the door has not been opened for 3 consecutive cycles or the door switch is open while the door is locked for more than 5 seconds.

Possible Causes/Procedure

-Door not opened during 3 consecutive cycles.

1. Open and close the door.
2. Verify CCU operation by running a Diagnostic Test or any cycle.

-Door switch open while door is locked.

1. Push the door and check if it is completely closed.
2. Verify CCU operation by running a Diagnostic Test or any cycle.

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DOOR SWITCH ERROR

If the door has not been opened for 3 consecutive cycles or the door switch is open while the door is locked for more than 5 seconds.

Possible Causes/Procedure

-Door not opened during 3 consecutive cycles.

1. Open and close the door.
2. Verify CCU operation by running a Diagnostic Test or any cycle.

-Door switch open while door is locked.

1. Push the door and check if it is completely closed.
2. Verify CCU operation by running a Diagnostic Test or any cycle.

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Open and close the door.
The door has to be opened between wash cycles.
Check the door switch/lock unit
using the diagnostics listed below.
If door is locked, Drain the unit.
Check wire harness for connections.
Check the touchpad/LED assembly.
Starting the test mode:
Close the door
Press Control On button
Select the DRAIN/SPIN cycle
Select NO SPIN by pressing the SPIN SELECT button,as needed,
Push Prewash Option button 4 times within 5 secs.
C:00 will show in the display.
To advance to the next step
Push Prewash Option button 2 times.
Here are the codes:
C:00 check door lock system actuator
C:01 Check cold water inlet valve flowmeter
C:02 check dispenser motor
C:03 check hot water dispenser
C:04 check basket rotation MCU,Motor
C:05 check heater sensor
C:06 check Drain pump
C:07 check Motor or motor control unit
C:08 check Motor, MCU control

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