I've reset as instructed and was able to start wash cycle, however, before making it through entire cycle the flashing light appeared again. Is it possible that I need to clean the lower assembly from any glass and / or debris? If so, what are the step by step instructions to remove the lower assembly?

Look at these: https://dl.dropboxusercontent.com/u/8010163/Kenmore%20Dishwasher%20Fault%20Codes.docx
https://dl.dropboxusercontent.com/u/8010163/Kenmore_Ultrawash_Dishwasher.pdf
Step one: Hold "Normal Wash" and "Start" together for 10 sec.
Step two: Press "Air Dry" and "High Temp Scrub" back and forth until "Quick Rinse" button turns on solid.
Step three: Press "Normal Wash" again followed by "Start."
Step four: Let machine run until you see green "Clean" light come on.
Step five: Press "Normal Wash" again and "Start" again.
That's it. (From another post)
https://dl.dropboxusercontent.com/u/8010163/Kenmore_Resetting%20fault%20codes.docx (Download link)