3:328 = Short circuit in the ACT, the drive motor or the motor cables.
The truck is braked by the motor brake until it stops.

Check
1.That the motor cables are undamaged and there is no short circuit between them or with B-.
2.The motor windings' resistance to the motor yoke, there should be no relationship.
3.Test using a new motor controller. If the error persists, the fault is probably an internal motor problem. Replace the motor and refit the old controller.

Both the frequency convertor boxes under the pedals are the same, you can swop there positions & see if the fault then moves to the hydraulic pump motor.