If all you are getting is a "clicking" sound, and you are sure it is coming from the starter, not the relay, i am almost 100% positive your starter solenoid is bad. Go buy a new starter for $80. Because if your starter is clicking, but not turning over the motor, then your ECU is fine. Because it is signaling the starter to turn. You can test this by simply pulling off the starter, (keep it hooked up to the wires) have a friend turn the key to start from inside the car, and if the starter motor is turning, then the starter is fine.