Would start with the seat switch, or operator presence switch. If this switch, which is under the seat, doesn't make up, you have no transmission operation and no hydraulics. You can unplug the harness and jump the switch out for test purposes. It is located on the right hand side of the seat.
Code E-03 is for ECM power supply circuit, no power to ECM for a predetermined time.I would first check the fuses and relays there might be a fuse/ relay box under the left hand foot step this is also where the VCM is. Ere will also be a relay Fuse box located next to the battery