Dishwasher program stops?

Have a diplomat integrated dishwasher ADP8242 about 5 years old. My problem is dosen't matter which program I use it stops just after 4 min. Normal use is the super wash and the light just stays lit, opening and closing the door dosen't continue the cycle. I've got to press and hold the prog buttonin untill the 2 outside lights glow, shut the door and the water empties and then stops. No fault codes are shown. Can anyone help please

Gordon
August 2008