Whirlpool duet sport washer WFW8300SW02 No agitation or spin problem

[Ahmed_gomaa]

Hi,

I have a Whirlpool duet sport washer WFW8300SW02. 

5 month ago it stopped spinning/draining. I cleaned up the pump. It still won't spin at the end of the cycle, then stopped even agitating at all. I measured the motor resistant according to the manual. By exclusion I found out that pressure switch is faulty. Changed the pressure switch and it worked fine for 5 month. But now it stopped again.

Current symptoms:

- Turns on fine, then when I start any cycle, door locks immediately and it will be stuck at add gourmet light on and will do nothing more than a clicking sound every few seconds (I will try to record the sound and post it). When I unplug it and plug it back, it starts filling immediately (with add gourmet and wash lights both on) without me pressing any buttons, dispenser motor rotates as if it is dispensing detergent, it fills and drains, fills again (rinsing) and drains. But no agitation or spinning at all. And then it gets stuck at 2 minutes remaining.

- Tried to run diagnostics test. The errors stored were: (F-21, F-26, and F-28) . After cycling through these codes, the test is supposed to start. But it just keeps flashing the light of spin/rinse and doing the clicking noise with nothing showing on the display until I unplug it.

- I also notice that the motor heats up really bad if I leave stuck at the clicking noise whether in the test mode or cycle mode.

- Clicking stops  (but it still doesn't start the cycle) if I disconnect the MCU connection at the CCU (MI3). It also stops when I disconnect the motor from the MCU by removing the connection at the MCU side. 

What I tried:

1) Replaced the pressure switch with another one again. Nothing changed.

2) Measured the resistance on the motor pins following the manual, all give 6 ohms as expected.

3) Tried to measure the electricity going into the CCU, reads 120 volts. But when I measure the two pins (MS2) where the CCU gives electricity to the MCU, I can't see any voltage readings (not sure if this should give 120v as well) Should it? 

Also the pins connected to the door lock don't read any voltage either (tried to measure as AC, but I am not sure if this is DC or something else).

 

Can you please help me diagnose the CCU or the MCU to see if they are faulty? How can I measure continuity there? Or otherwise if you have any ideas please let me know.

[lvasquez11]

is the clicking from one the boards or latch 

 

a defective door latch could be causing communication error codes 

Part number: WPW10253483

[Ahmed_gomaa]

The clicking comes from the back. Looked like it was coming from the MCU.

On the other hand, the door locks with not problems.

[lvasquez11]

power to MCU is completed by  door latch.   take a look at wire diagram.

disconnect MI3 harness to mcu n cycle unit n check results