My Kitchen Aide Dishwasher KUDE20FBSS1 gives me an LED error code of 8-4, what does that mean?

Start with a reset, Note the model you have requires a different reset sequence.

http://www.ehow.com/info_8630172_reset-sequence-kitchenaid-dishwasher.html (http://www.ehow.com/info_8630172_reset-sequence-kitchenaid-dishwasher.html)

Certain Models


Some KitchenAid dishwasher models require a slightly different reset process. For the KitchenAid KUDS01FLSS0 dishwasher, a different reset is necessary if the "Clean" light flashes 7 times in a row. In this case, press the "Sani Rinse" button, followed by the "Energy Saver Dry" button, followed by the "Sani Rinse" button and then the "Energy Saver Dry" again. All of the dishwasher lights will illuminate. Wait 10 seconds, then press "Cancel" to complete the reset process.

In addition,

Kitchenaid Dishwasher KUDR 24SE Troubleshooting | eHow (http://www.ehow.com/how_7011846_kitchenaid-dishwasher-kudr-24se-troubleshooting.html)

Kitchen Aid Dishwasher Troubleshooting | eHow (http://www.ehow.com/way_5196473_kitchen-aid-dishwasher-troubleshooting.html)

KitchenAid Dishwasher Error Codes | eHow (http://www.ehow.com/list_7215705_kitchenaid-dishwasher-error-codes.html)

I have found no such error code for this model. Could they be F08, and F04?

Here is a manual: https://dl.dropboxusercontent.com/u/8010163/Kitchenaid%20Briva%20Dishwasher.pdf
Look here to find out what it means: Appliance Fault Codes - AppliancePartsPros.com (http://www.appliancepartspros.com/repairtips/repairtips_appliance+fault+codes.aspx#Whirlpool%20 Duet%20Front%20Loading%20Gas%20and%20Electric%20Dr yer%20Fault%20Codes)