The Frigidaire Appliances company designed most of its dishwashers to visually alert and display to users that the door is ajar, via the "CL" code. The dishwasher won't start pumping in hot water or rotating the spray arms until the door is secure. Even if this safety feature were to malfunction, you would hear and see water spilling out the top and sides of the appliance. This may seem unnecessary, but the message could help you avoid water damage to your kitchen floor and basement ceiling. Getting rid of this code is nearly intuitive, but you should check for any blockages before going back to dishwashing as usual.
Open the Frigidaire dishwasher's door, completely and carefully. Don't swing the door open to where hot water, dishwasher detergent and rinse aid could come in contact with your skin or spill onto the floor.
Look for objects that might prevent the dishwasher's door from securely closing. Many Frigidaire dishwashers have a rubber gasket around the door frame that forms an airtight seal to keep dishwashing water and food particles in. However, fallen utensils and large food particles could be preventing the door from forming a good seal. Use a paper towel to wipe around this rubber gasket and its contact surface.
Close the door. Press firmly and listen for the latch to engage as a part of the locking mechanism. The Frigidaire dishwasher should automatically resume the current cycle.