error code

[scooter]

hi guys just had the car go into limp mode got home connected computer read codes P1618 reset went back out and limp again code again was P1618 any body have a clue what this is looked on the web and so many explanations

[Laserowl]

Possibly lost speed sensor input, but lots can cause this error, ABS module fault etc etc.
Do you have any other lights on dash codes etc ?

[scooter]

incorrect gear ratio 5 i think