Digital Fuel Gauge - Displays CO Error Code
Article No.92-23-3
11/04/92
^ GAUGE - FUEL - ELECTRONIC - FUEL LEVEL INDICATED ON GAUGE MAY SHOW INCREASE AS FUEL IS CONSUMED AND "DTE" MAY CHANGE
^ GAUGE - FUEL - ELECTRONIC INSTRUMENT CLUSTER - DIGITAL GALLONS MAY INTERMITTENTLY DISPLAY A "CO" ERROR CODE AND ILLUMINATE TOP/BOTTOM DIAGNOSTIC BARS
FORD:
1991-92 TAURUS
1992 CROWN VICTORIA
LINCOLN-MERCURY:
1991-92 CONTINENTAL, SABLE, TOWN CAR
1992 GRAND MARQUIS
LIGHT TRUCK:
1991-92 AEROSTAR
ISSUE:
The electronic instrument cluster fuel gauge digital gallons (liters) may intermittently display a "CO" error code and illuminate the top/bottom diagnostic bars. In addition, the level of fuel indicated on the gauge may show an increase as fuel is consumed and the DTE may change. These conditions may be caused by the fuel sender or the EIC assembly.
ACTION:
Perform the diagnostic and repair procedures detailed below. If necessary, replace the fuel sender and/or EIC as required.
NOTE:
FIRST PERFORM TSB ARTICLE 92-21-5 TO ALL 1992 CROWN VICTORIA/GRAND MARQUIS VEHICLES BUILT PRIOR TO 3/1/92.
1. Confirm that the fuel sender wiring is properly seated.
2. Remove the fuel sender. Refer to the appropriate Service Manual, Section 10-01, for removal procedure.
3. Check the resistance.
a. Attach a digital ohmmeter (set to 200 ohms) to the fuel sender pins.
b. Check resistance of the fuel sender by slowly moving the float arm from empty to full and back to empty 10 times, Figure 1.
c. The resistance should increase steadily from 10 ohms (empty) to 172 ohms (full).
d. The sender is defective if the resistance spikes, increases above specification, or indicates an open circuit at any time during the test.
4. If the fuel sender is found to be defective, replace the sender and continue with Step 5.
NOTE:
ON ALL SERVICE REPLACEMENT FUEL SENDERS, PERFORM STEPS 3 AND 5 BEFORE INSTALLATION. BEFORE TESTING A SERVICE REPLACEMENT FUEL SENDER, MOVE THE SENDER FLOAT ARM UP AND DOWN ITS TOTAL TRAVEL RANGE 20 TIMES TO CLEAN OFF ANY OXIDATION FROM CONTACT SURFACES DUE TO STORAGE.
5. Place a finger under the float and jiggle the float (to stimulate actual float action in the fuel tank) while raising and lowering the sender float arm through its total travel range, Figure 2.
a. Repeat jiggle test 10 times.
b. The sender is defective if the resistance spikes, increases above specification, or indicates an open circuit at any time during the test.
c. Replace the sender if defective. Refer to the Parts Block in this article for correct parts usage.
d. Continue with Step 6.
6. Install the fuel sender.
a. Check the fuel sender to electronic instrument cluster wiring and connectors for proper continuity.
b. Correct any concerns noted and continue with Step 7.
7. Check the digital readout.
NOTE:
THIS STEP DOES NOT APPLY TO CONTINENTAL.
a. Test drive the vehicle one or two (2) blocks to stabilize the fuel gauge system.
b. Park the vehicle on a level surface.
c. Turn the ignition switch to "OFF" for about 60 seconds before proceeding.
CAUTION:
DO NOT INTENTIONALLY ROCK THE VEHICLE WHILE PERFORMING THE NEXT STEP IN THIS TEST!
d. While sitting in the vehicle, turn the ignition key to "RUN" and leave the transmission in "PARK".
e. If the digital gallons (liters) readout is highly erratic (continually "Hunts" for a value), replace the electronic instrument cluster with an upgraded EIC assembly by calling your EIC Service Center. Please indicate that the instrument cluster is being ordered as a result of performing this TSB.
^ Eastern EIC Service Center:
1-800-262-9606
^ Western EIC Service Center:
1-800-321-6969
^ Canadian EIC Service Center:
1-800-663-9974
NOTE:
UPGRADED ELECTRONIC INSTRUMENT CLUSTERS WILL NOT BE AVAILABLE FOR TOWN CAR AND CROWN VICTORIA/GRAND MARQUIS UNTIL DECEMBER, 1992. AN UPDATED ELECTRONIC INSTRUMENT CLUSTER IS NOT AVAILABLE FOR THE 1991 TAURUS/SABLE AT THIS TIME.
Part Number/Name Chart
Warranty, Operation and Description