Compensator immersed in water.
Circuit out of calibration.
Tank unit(s) out of circuit.
Defective pins in connector on fuel probes and wing harness used to connect fuel probes.
Fuel quantity gauge pegs down scale against stop.
Defective pins on connectors on both gauge and probes.
Nacelle probe body is making contact with metal braided hose inside of nacelle tank.
One or more tank units out of circuit (when fuel level low).
Fuel quantity indicator needle pegs up scale against stop.
Indicator out of calibration.
Faulty tank unit.
Water in fuel.
Fuel quantity sluggish.
Defective tank unit.
Dirty fuel tanks.