No that's exactly correct. Has the contactor been able to close before? This error could be appearing because the P contactor isn't closing or there is a voltage drop across the contactor. This can happen if the tips are burnt or worn. With the battery at 35v that may be the issue, the battery should be atleast 36v for the truck to function.

Otherwise I recommend starting to swap components in the circuit. If you can get another battery, fuses, etc. that would be good to fully rule out what is good/bad.