dynamics

According to troubleshooting section of AMM If the fuel quantity indicator displays zero kilograms and presents Error Code 2, this signifies the presence of a short circuit within the compensator unit(HI-Z to COMP LO-Z). An Error Code 4 indicates either an open circuit or a short circuit within the TANK LO-Z line.Should Error Code 5 be displayed, it denotes a short circuit in tank unit (HI-Z to TANK LO-Z).Finally, the appearance of Error Code 10 implies the existence of either an open circuit or a short circuit within the HI-Z line itself.
Could you please clarify the technical meaning of the terms 'HI-Z to COMP LO-Z', 'TANK LO-Z line', 'HI-Z to TANK LO-Z', and 'HI-Z line' within the context of the fuel quantity measurement system?