This is likely to be a problem with the wire connection. We would suggest you check all the wire connections on the treadmill starting at the base of the machine and working your way up to the right hand handrail connection.
If the wires have been squeezed together, cut, dented or pulled this could have an adverse effect on the performance of the machine.
It is also worth checking to see if the pins in the male connections are straight as again this could affect the performance of the machine.
If you have checked your wire connections from base to top and you are still experiencing problems then please contact us.