Although you have cleaned out the drain pump, you still may have a clog in the drain line somewhere, or you have a pump that has failed. A noteable area that gets clogged often with small articles of clothing (such as wash cloths, socks, underwear, etc.), is the drain line that runs from the bottom of the wash tub to the inlet side of the drain pump. If you have checked this, the pump clean out reservoir, and all remaining drain lines after the pump, you more than likely have a defective pump. It doesn't take much to damage them, and just because you can hear it running, does not necessarily mean it is working properly. Often, the impeller blades are damaged, impeller shaft becomes stripped, or pump motor windings are worn. The best solution the manufacturer offers is to replace the drain pump. Searspartdirect.com carries the part. Just type in your complete model number and the drain pump will be located under the "Pump and Motor" heading as item 10 (I believe). The pump is sold as a complete assembly which includes the pump housing and the motor. If you need instructions on how to replace the pump, just click on this link:

http://www.fixya.com/support/r401845-replacing_drain_pump_whirlpool_duet

If you still don't believe me and wish to doublecheck your efforts before purchasing any replacement parts, the next link explains the "F02" error and how to attempt to correct it:

http://www.fixya.com/support/r615268-f02_error_code_whirlpool_duet_kenmore

I hope this information is helpful to you. Let me know if you require additional assistance.