A squeaking sound when a dishwasher door opens or closes is typically the result of metal or plastic parts rubbing together. The hinges on virtually all dishwashers move vertically into and out of the left and right sides of the appliance at the base of the door. You should be able to stop the squeaking yourself with an application of lubricant, unless the hinges are damaged or bent, which may require the services of a trained technician to replace the door and prevent leaks.
Turn off power to the dishwasher at the circuit breaker.
Release the door latch and open the dishwasher door to listen for the squeak. Isolate the sound by listening on one side, then the other, so you know where to work.
Take out the screws in the left and right edges of the bottom access plate below the door. Pull off the plate and set aside. Look at the hinges where they enter the sides of the cabinet along the bottom left and right sides of the dishwasher door.
Lower the door to the horizontal position, parallel to the floor.
Spray a short burst of silicon-based lubricant on each metal hinge that squeaks at its top and on its underside, below the space where the access panel attaches to the appliance. Raise and lower the door a few times to work the lubricant into the hinges and stop the squeaking.
Reattach the access plate with the screws and restore electricity to the dishwasher.