Fuel Gauge - Erratic Readings

88-16



Fuel Gauge - Erratic Readings - Anti-Slosh Module and Fuel Tank Sender Unit Test

MODEL
92 MY XJS

DATE
7/92



ISSUE:

An anti-slosh module is incorporated into the fuel gauge circuit on 1992 MY XJS vehicles. The anti-slosh module inhibits fuel gauge needle movement and controls the low fuel warning light.

Incorrect fuel gauge readings can be caused by anti-slosh module failure.

Intermittent fuel gauge needle flicker or swinging to empty while driving can be caused by an open circuit in the fuel tank sender unit.


NOTE:
It is normal for the fuel gauge needle to move toward "empty" during cornering. The needle will then return slowly to the correct position.


ACTION:

For complaints of erratic fuel gauge operation, refer to the Instrument Pack wiring diagram in the 1992 MY XJS Electrical Guide (S 72/92), and use the following diagnostic and test information:





Component Information






Anti-slosh Module - Terminal Voltages






Anti-slosh Module - Tests:

Refer to the diagnostic Chart.

Fuel Tank Sender unit - Tests:

^ Remove the fuel tank sender unit. Refer to Section 88.25.32 of the 1992 XJS Repair Manual.

^ Use a DVOM to check sender unit resistance between the top and center terminals.

^ Move the float arm slowly from lower to upper stops.

The resistance should change smoothly between the following values:

Lower end stop (EMPTY) = 240 - 250 ohms
Upper end stop (FULL) = 16 - 18 ohms

If there is an open circuit at any point as the float arm is moved, or if the gauge needle flickers and swings to zero intermittently and the anti-slosh module tests indicate that is functioning properly, replace the sender unit and retest the system.






PARTS INFORMATION






WARRANTY INFORMATION