Without a controller, your PlayStation 2 console is pretty much useless. The controller is your only means of communication with the console, allowing you to tell the game everything you want it to do. If you notice problems with your PS2 controller, the problem doesn't always warrant a call to Sony support or a replacement. Try to reset the PS2 controller to bring it back to a functional state.
Power off your PlayStation 2 console by holding the front power button until the light turns from green to red.
Disconnect your PlayStation 2 controller from the console and plug it back into the first controller port. Make sure it's plugged in completely.
Lay the controller on the ground with the analogue sticks and buttons facing up. Make sure nothing is touching either analogue stick.
Press the power button on the PS2 to turn it back on.
Use your thumbs to rotate both analogue sticks in a complete circle simultaneously.
Press the analogue button in the centre of the colour to enable or disable the analogue function on the controller. Some games do not allow you to disable this feature, and the light does not turn off. Other games do not support the analogue feature. Refer to the game case or the user manual for information specific to the game in question.
Adjust the controller settings in the game. Many games allow you to reconfigure the controller layout. How and whether this can be done varies from game to game. Refer to the user manual for details specific to the game you're playing.
Many third-party wireless controllers have a small reset button (depressed using a paper clip) or a synchronisation button that resets the controller in one easy step. How this is done varies from brand to brand, so refer to the controller's manual for information.
Try your controller on another PS2 or in the other controller port if it doesn't function even after resetting. If your controller still doesn't function, you may need to contact Sony customer support or buy a replacement.