You should have a tech data sheet should located behind the bottom access panel near your floor which should explain the meaning of this error code.
Models without a digital display signal error codes by flashing the Clean light in a pattern unique to the error. The light first flashes the first number of the error code, pauses for 2 seconds and then flashes the second number of the code. Here is the error code chart for Kenmore MircoClean dishwashers: searspartsdirect.com/diy/error-codes/dishwasher-repair/1234583/kenmore-microclean-he-dishwasher/0582
According to the chart, and 8-4 code is a Drain pump motor failure
Unplug the dishwasher and check the wire harness connections between the drain pump and the electronic control board. Reconnect any loose wires and repair any damaged wires. If the wiring is okay, check for and clear any debris you find inside the drain pump that may be preventing the impeller from spinning. If the drain pump is clear of debris, you'll likely need to replace the drain pump.
You can find all parts, diagrams, and your owners manual on www.SearsPartsDirect.com
, just enter your full model number.
How to replace a dishwasher drain pump DIY repair guide: searspartsdirect.com/diy/repair-guide/how-to-replace-a-dishwasher-drain-pump
If you'd rather have a professional repair, call Sears Home Services at 1-800-4-MY-HOME.