code, low voltage,pcm on 2001 Kia Sephia

service engine light code said pcm,low curent,loose conection,car started using gas

Can you remember the fault code number it would look like "P0420" or "P1234"? Low voltage can be caused by poor grounds which Ihave seen bulletins on from Kia. Kia as a car manufacturer put a lot of there technical training and manuals on line for free. If you can give me the code number I can give you more information. Check out Kia's free website