The dishwasher's power should be disabled prior to tightening the door latch. The appliance's power can be turned off from the kitchen's power supply line located in your home's circuit breaker or fuse box. Once the latch is tightened it is safe to restore power to the kitchen area.
Latch maintenance of your dishwasher is achievable by tightening the door latch located at the top of the door with a Phillips screwdriver. Turning the blade end of the screwdriver into the latch's screw secures the door latch in place, and eliminates the need to slam the door in order to properly close the dishwasher.
A loose latch prevents the dishwasher from starting, as the dishwasher detects the door is not closed and will not start a cleaning cycle. The dishwasher's latch locks during a wash cycle, and remains locked until the cycle finishes and the appliance comes to a complete stop.
A loose latch is preventable by gently pulling the door when opening it, and firmly closing the door to lock the latch. Slamming the dishwasher's door shut is hard on the appliance and gradually loosens the door's screws. A half-turn of the screw after every few cleaning cycles prevents the latch from becoming too loose, and does not require professional service to tighten the door's screws.