My Frigidaire Affinity washer is not draining. I've removed and cleaned out the pump discharge hose, and disconnected the inlet pump hose and cleaned that. Water flows freely through both hoses, but still won't drain. I hear the pump running for approximately one minute, then stops. Does this 4-5 times before "PAU" blinks. Error code is E21.

I'm assuming the pump filter is the problem. If that's the case, how do I clean it? I want to make sure I do it right the first time as I've already opened up the machine twice to clean hoses and still not working. Do I need to remove the pump or clean in place? Use shop vac or air compressor?

Am I overlooking anything, could there be another problem?

Thanks.