H4-00 on Sharp means that the temperature inside the printer is too low. That is usually the fuser lamp, and sometimes the temp sensor jammed.
Only when the problem is a jammed temp sensor or a jammed control board you can reset the machine by doing a reset.
You try reset from simulation mode by following procedure below:
Clear key >>Interrupt key >> "0" key >> Interrupt key >> Main code >>Start key >> Sub code >> Start key
If the error remains, that means that the fuser is really bad and must be replaced.
this happen you need to have the fuser unit replaced, if that does not
fix the problem the technician will replace the temperature sensor.