Just recently, my whirlpool duet GHW9100L washing machine has been having issues where it stops at the drain cycle with a F/02 error (so it doesn't drain and and doesn't do the superfast final spin).
I have cleaned out the water pump and inspected both hose attachments for debris. There was some debris that I cleaned out. When I then resumed from where i left off it seemed to work. SO then I ran a small wash and it worked (drained properly). But then I tried another wash and it stopped during the drain cycle with the F/02 error. So, I clicked cancel and then clicked start again to resume. It then completed the load properly.

Finally, I did a diagnostic test (ie C:00) and everything worked as it should.

So from what I concluded, it seems the drain pump does work just seems like it does not always drain when it should and this the cycle gets stuck. From what I've read and concluded it seems like it could be one of these 3 issues:

Water PUMP
Water Level Pressure switch
CCU

Anyone have any thoughts or suggestion on where to go from here or if they can give clues as to what it could or could not be?

Thanks.

Now that you mention it there is some rattling sound from the pump. I just ran another load and now its stuck on the rinse cycle. I hear the pump going and a rattling sound. I tried cancelling and starting again, but not helping and now its showing a SUD error. When I can get the machine emptied and cleared I will then check the pump. TO be clear is the impeller that thing that rotates in the plastic housing area. Almost looks like a fan?
Assuming it is the pump impeller, can this be fixed or should the entire pump be replaced?

By the way, I did try to blow through the small hose that connects to the sensor previously. I couldn't seem to blow through it, but maybe I did not try hard enough (I also only cupped my hands so I wouldn't blow directly through it instead of washing the other end and blowing directly). I figured the way it was attached at the other end would make it difficult to blow through. But I will try that again.

Let me know your thoughts and I will then do some other testing.

I think it does sound like it. By the way, I figured I could outsmart my machine and get the water discharged by cancelling the other cycle (it kept getting stuck in rinse) and then going into diagnostic mode. So I did that and diagnostic mode also got the F02 error and the pump was not discharging the water. It was definitely trying to do something, but no water was coming out. Any chance this could be related to the sensor or if the pump motor is operating but not water discharging, then its a pump issue? I'm still going to get a replacement pump no matter what, but curious.

Thanks.

Thanks for your help. Will let you know if its not the pump.

My drain pump started to go with these similar issues
(same model). My advice, order the new one, it's also an upgrade from the old one as they replaced it deeming the old one insufficient.
Super easy fix and the headache will be gone.