code 18
Deadman Error

Reason: Deadman state descrepancies between Trucktracker steer controller and Vehicle Manager

Corrective actions:
- check connections between JS9-6 and J2-4
- check connections between JS9-1 and J1-3
- Replace steer controller
- Replace Vehicle Manager

I would make sure the deadman pedal switch is operating correctly, then if there are any safety arm switches (if it has safety arms on the sides of the platform) make sure they are working properly. This may not be it but you should make sure the TM and TT are getting the deadman signal from the pedal.