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Test E: Fuel Gauge Inaccurate/Inoperative: Notes

  1. If instrument panel cluster diagnostic system check has been performed, go to next step. If instrument panel cluster diagnostic system check has not been performed, go to INSTRUMENT PANEL CLUSTER DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  2. Disconnect in-line Black 8-pin harness connector C400. In-line harness connector C400 is located under vehicle, near front of fuel tank. Turn ignition switch to RUN position. Connect Signal Generator and Instrument Panel Tester (J 33431-C) between in-line harness connector C400 terminals "C" and "D", fuel level sensor signal circuit and fuel level sensor low reference circuit (female terminal side). See Figure . Connect DVOM to signal generator and instrument panel tester. Vary resistance on signal generator and instrument panel tester between 50-250 ohms comparing reading to fuel level specifications table. See FUEL LEVEL SPECIFICATIONS  table. If fuel gauge displays correct readings, go to step  4 . If fuel gauge does not display correct readings, leave signal generator and instrument panel tester connected and go to next step.
    FUEL LEVEL SPECIFICATIONS

    Fuel Gauge Display Ohms Fuel Level Fuel Remaining
    E 278 4 Volts .66 Gals.
    1/4 196 3.3 Volts 5.28 Gals.
    1/2 141 2.7 Volts 8.84 Gals.
    3/4 91 2.1 Volts 12.8 Gals.
    F 500 1.2 Volts 15.71 Gals.
    Low Fuel Indicator On 256 3.8 Volts 1.98 Gals
    3. NOTE: Turn ignition switch to OFF position momentarily between resistance settings to quickly update scan tool display.
  3. Connect scan tool to Data Link Connector (DLC). DLC is located under left side of instrument panel. Turn ignition switch to RUN position. Vary resistance from 50-280 ohms comparing reading to fuel level specifications table. See FUEL LEVEL SPECIFICATIONS  table. Using scan tool, observe FUEL LEVEL GAUGE (voltage) parameter in IPC data list. If scan tool parameter does not display correct fuel level voltage, go to next step. If scan tool parameter displays correct fuel level voltage, go to step  9 .
  4. Check for poor, loose or corroded terminals in fuel level sensor harness connector. Check for high resistance in Blue/Black wire between fuel pump and sender harness connector terminal "D" and in-line harness connector C400 terminal "C". See Figure and Figure . Check for high resistance in Black wire between fuel level sensor harness connector terminal "C" and in-line harness connector C400 terminal "G". Check for a misaligned fuel level sensor or deformed fuel tank. If problem is found, make necessary repairs and go to step  12 . If no problem is found, go to step  7 .
  5. Check for high resistance in fuel level signal circuit (Blue/Black wire) between fuel pump and sender harness connector terminal "D" and IPC harness connector terminal No. 20. See Figure and Figure . If no problem is found, go to next step. If problem is found, make necessary repairs and go to step  12 .
  6. Check for high resistance in fuel level sensor low reference circuit (Black wire) between ground and fuel level sender harness connector terminal "C". See WIRING DIAGRAMS  . If problem is found, make necessary repairs and go to step  12 . If no problem is found, go to step  9 .
  7. Remove fuel pump and sender. See FUEL PUMP & SENDER ASSEMBLY  under REMOVAL & INSTALLATION. Check for stuck fuel level sensor, or foreign material in fuel tank. If no problem is found, go to next step. If problem is found, make necessary repairs and go to step  12 .
  8. Using DVOM connected to fuel level sensor harness connector terminals "C" and "D", measure resistance while moving fuel level sensor up and down. See Figure . Resistance should change smoothly from 50-280 ohms. If resistance changes as specified, go to DIAGNOSTIC AIDS  . If resistance does not change as specified, go to step  10 .
  9. Check for poor, loose or corroded terminals in IPC harness connector. If problem is found, repair as necessary and go to step  12 . If no problem is found, go to step  11 .
  10. Replace fuel pump and sender assembly. See FUEL PUMP & SENDER ASSEMBLY  under REMOVAL & INSTALLATION. After repairs are made, go to step  12 .
  11. Replace IPC. See INSTRUMENT PANEL CLUSTER  under REMOVAL & INSTALLATION. After repairs are made, go to next step.
  12. Using scan tool clear ECM and IPC DTCs. Operate system to verify repair. If system operates normally, testing is complete. If system does not operate normally, go to step  2 .
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