i may have already responded to another post you made about this but here goes again
code/fault 30 is pump motor circuit fault
possible causes are:
- faulty line contactor
- faulty regeneration contactor
- faulty D1P diode
- faulty pump motor wiring
- faulty head capacitor
- faulty T1P IGBT
- faulty CS3 current sensor
- faulty wiring in other parts (associated with pump circuit)
- faulty logic card
- faulty drive board

so there you have it, many many things that can cause this fault.
most likly suspects would be D1P diode, pump motor wiring, head capacitor, T1P IGBT or Drive board. Drive boards are fairly common with these trucks to go out.