If the console takes batteries, replace them. If this does not work or your console does not require batteries, check the reed switch or optic sensor. Reed Switch: Unplug the treadmill and remove the motor hood cover. The reed switch is mounted on the frame next to the front roller pulley. There is a magnet glued into the front roller pulley. When adjusting the reed switch, make sure it is pointing directly at the magnet. Move the tip of the reed switch within 1/8" of the magnet. Also, check to see that the wire is not damaged, and is connected to the console.
Optic Sensor: Unplug the treadmill and remove the motor hood cover. The optic disk and sensor are located either at the end of the motor or the right hand side of the front roller. The optic disk spins between two sensors on the optic switch. The disk must spin freely without touching either sensor. The sensors can be moved by loosening the adjustment bolt holding the switch to its bracket. The switch can then be slid. Center the disk.
Adjust and clean very softly.