Guitar Hero Grip

Hey, i bought Guitar Hero On Tour Decades for DS on Christmas and sometimes (sometimes!!) It doesn't detect the blue button on de grip. What could cause this?

possibly faulty hardware, or you arent pressing the button right for it to detect it.

Well, sometimes i have to unplug>replug it in the GBA slot.

sounds like the grip has an intermittent fault.

Well, it seems to be working now, i just it might be random as because it has only happened 3 times.