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Test D: Fuel Gauge Inaccurate

  1. Turn ignition switch to LOCK position. Connect New Generation Star (NGS) tester to Data Link Connector (DLC). DLC is located below left side of instrument panel, to right of steering column. Turn ignition switch to RUN position. Using NGS tester, retrieve and record continuous instrument cluster and Rear Electronic Module (REM) DTCs. Clear instrument cluster and REM DTCs. Using NGS tester, perform instrument cluster and REM self-test. If REM DTC B1201 and/or instrument cluster DTC U1131 are not retrieved, go to next step. If REM DTC B1201 and/or instrument cluster DTC U1131 are retrieved, go to step  6 .
  2. Using NGS tester, select instrument cluster active command FUEL LEVEL CONTROL. Trigger FUELLEVEL. Scroll FUEL LEVEL to 0 percent, 50 percent, then 100 percent while observing fuel gauge. Fuel gauge should display empty at 0 percent, half at 50 percent and full at 100 percent. If fuel gauge operates as described, go to next step. If fuel gauge does not operate as described, replace instrument cluster.
  3. Turn ignition switch to LOCK position. Disconnect Fuel Delivery Module (FDM) 4-pin harness connector. FDM is located, on top of fuel tank. Measure resistance between FDM terminals No. 2 and 3 (component side). See Fig 1 . Resistance should be 14-18 ohms when fuel tank is empty and 151-159 ohms when fuel tank is full. If resistance is as specified, go to next step. If resistance is not as specified, replace FDM.
    4. NOTE: It may be necessary to lower fuel tank to access Jet Pump Module (JPM) harness connector.
  4. Disconnect Jet Pump Module (JPM) harness connector. JPM is located, on top of fuel tank. Measure resistance between JPM terminals No. 2 and 3 (component side). See Fig 1 . Resistance should be 17-21 ohms when fuel tank is empty and 156-164 ohms when fuel tank is full. If resistance is as specified, go to next step. If resistance is not as specified, replace JPM.
  5. Visually inspect fuel tank. If fuel tank is okay, inspect float and float rod for damage, and repair or replace components as necessary. If fuel tank is damaged, repair or replace fuel tank as necessary.
  6. Turn ignition switch to LOCK position. Disconnect Rear Electronic Module (REM) harness connectors C420c and C420d. REM is located on right side of luggage compartment, above battery. See Figure . Measure resistance between ground and REM harness connector C420d terminals No. 15 (White/Red wire) and No. 16 (White/Blue wire). See Figure . Measure resistance between ground and REM harness connector C420c terminal No. 23 (Brown wire). If any resistance is 10 k/ohms or less, go to next step. If all resistances are more than 10 k/ohms, go to step  8 .
    7. NOTE: It may be necessary to lower fuel tank to access Jet Pump Module (JPM) harness connector.
  7. Disconnect Fuel Delivery Module (FDM) 4-pin harness connector. FDM is located, on top of fuel tank. Disconnect Jet Pump Module (JPM) harness connector. JPM is located, on top of fuel tank. Measure resistance between ground and REM harness connector C420d terminals No. 15 (White/Red wire) and No. 16 (White/Blue wire). Measure resistance between ground and REM harness connector C420c terminal No. 23 (Brown wire). If any resistance is 10 k/ohms or less, repair short to ground in appropriate circuit between REM and FDM, or between REM and JPM. If all resistances are more than 10 k/ohms, replace FDM and/or JPM as necessary.
  8. Disconnect Fuel Delivery Module (FDM) 4-pin harness connector. FDM is located, on top of fuel tank. Disconnect Jet Pump Module (JPM) harness connector. JPM is located, on top of fuel tank. Measure resistance in White/Red wire between REM harness connector C420d terminal No. 15 and FDM harness connector terminal No. 2. See Figure and Fig 2 . Measure resistance in White/Blue wire between REM harness connector C420d terminal No. 16 and JPM harness connector terminal No. 2. Measure resistance between REM harness connector C420c terminal No. 23 (Brown wire) and JPM harness connector terminal No. 3 (Brown/Blue wire). Measure resistance between REM harness connector C420c terminal No. 23 (Brown wire) and FDM harness connector terminal No. 3 (Brown/Red wire). If all resistances are 5 ohms or less, go to next step. If any resistance is more than 5 ohms, repair open in appropriate wire.
  9. Turn ignition switch to RUN position. Measure voltage between ground and REM harness connector C420d terminals No. 15 (White/Red wire) and No. 16 (White/Blue wire). Measure voltage between ground and REM harness connector C420c terminal No. 23 (Brown wire). If voltage does not exist at any terminal, go to next step. If voltage exists at any terminal, repair short to voltage in appropriate wire between REM and FDM, or between REM and JPM.
  10. Measure voltage between ground and FDM harness connector terminals No. 2 (White/Red wire) and No. 3 (Brown/Red wire). Measure voltage between ground and JPM harness connector terminals No. 2 (White/Blue wire) and No. 3 (Brown/Blue wire). If voltage does not exist at any terminal, replace FDM and/or JPM as necessary. If voltage exists at any terminal, repair short to voltage in appropriate wire between REM and FDM, or between REM and JPM.
Fig 1: Identifying Fuel Delivery Module & Jet Pump Module Terminals (Component Side)
G00011089Courtesy of FORD MOTOR CO.
Fig 2: Identifying Fuel Delivery Module & Jet Pump Module Harness Connector Terminals
G00011090Courtesy of FORD MOTOR CO.
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