ION, L-Series, S-Series 1999-2005
The fuel level sending unit can be most accurately diagnosed while still in the vehicle with a full or empty fuel tank.
Be sure that the ignition is turned
. Open the trunk lid or liftgate and turn back the carpet against the left side.
Unplug the in-line fuel connector.
With the ohmmeter probes placed at connector pins B and C of the sending unit side connector, check the resistance and compare it to the figures in the appropriate chart.
If the resistance reading(s) do not coincide with the figures in the chart, replace the fuel level sending unit.
Attach the in-line fuel connector and reposition the carpet.