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Test C: Fuel Gauge Inaccurate/Inoperative: Testing

NOTE: For comparison of fuel level indicated on IPC and resistance settings on signal generator and instrument panel tester. See FUEL LEVEL SPECIFICATIONS  table to convert from resistance to fuel level percentage.
  1. If instrument cluster diagnostic system check has been performed, go to next step. If instrument cluster diagnostic system check has not been performed, perform instrument cluster diagnostic system check. See INSTRUMENT PANEL CLUSTER DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
    2. NOTE: Verify Signal Generator And Instrument Panel Tester (J-33431-C) resistance settings are correct with a DVOM. Resistance setting on tester should be from 40-250 ohms.
  2. Disconnect fuel pump connector at fuel pump. Connect tester between signal circuit (Purple wire) and low reference circuit (Black wire) of fuel level sensor harness connector. See Figure . Turn ignition on, with engine off. Using tester, vary resistance from 40-250 ohms. See FUEL LEVEL SPECIFICATIONS  . If fuel gauge displays correct fuel level, go to step  4 . If fuel gauge does not display correct fuel level, go to next step.
  3. Turn ignition off. Connect scan tool to Data Link Connector (DLC). Turn ignition on, engine off. Using scan tool, select INSTRUMENT PANEL CLUSTER, SPECIAL FUNCTIONS, then IPC GAUGES. Using scan tool, observe FUEL LEVEL % parameter in PCM data list. Turn off ignition momentarily between resistance settings in order to quickly update scan tool display. If scan tool displays correct fuel level percentage, go to step  11 . If scan tool does not display correct fuel level percentage, go to step  5 .
  4. Inspect for following items:
    • A poor connection at harness connector of fuel level sensor
    • A misaligned fuel level sender
    • A deformed fuel tank
    • A high resistance in the signal circuit or low reference circuit, of the fuel level sensor between fuel level sensor and IPC.

    If a problem was found, repair as necessary. After repair, go to step  13 . If no problem was found, go to step  7 .

  5. Test signal circuit of fuel level sensor for a high resistance. If a problem was found, repair circuit as necessary. After repair, go to step  13 . If no problem was found, go to next step.
  6. Test low reference circuit of fuel level sensor for a high resistance. If a problem was found, repair as necessary. After repair, go to step  13 . If no problem was found, go to step  9 .
    7. NOTE: Fuel level sender is an integral part of fuel pump assembly.
  7. Remove fuel level sender from fuel tank. See FUEL PUMP under FUEL SYSTEMS in appropriate REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE. Check for a stuck fuel level sender (i.e., fuel strainer interfering with sender float arm) or foreign material in fuel tank. If no problem was found, go to step  9 . If a problem was found, repair as necessary. After repair, go to step  13 .
  8. Using DVOM, measure resistance of fuel level sensor while moving float arm. Observe both analog and digital displays on DVOM. Resistance should change smoothly. If resistance changes smoothly, go to DIAGNOSTIC AIDS  . If resistance does not change smoothly, go to step  10 .
  9. Check for poor connection at PCM harness connectors. If problem is not found, go to step  12 . If problem is found, repair source of high resistance or open circuit as necessary, go to step  13 .
    10. NOTE: Fuel level sender is an integral part of fuel pump assembly.
  10. Replace fuel level sender. After repair, go to step  13 .
  11. Replace instrument cluster. See INSTRUMENT PANEL CLUSTER  under REMOVAL & INSTALLATION. After repairs, go to next step.
  12. Replace PCM. See POWERTRAIN CONTROL MODULE  under REMOVAL & INSTALLATION. Perform set up procedure on Powertrain Control Module. See POWERTRAIN CONTROL MODULE/ PROGRAMMING ON BOARD  and POWERTRAIN CONTROL MODULE/ PROGRAMMING OFF BOARD  under PROGRAMMING. After repair, go to next step.
  13. Connect all disconnected components. Check system for proper operation. If system operates properly, test is complete. If system does not operate properly, go to step  3 .
FUEL LEVEL SPECIFICATIONS

Fuel Gauge Indication Ohms Fuel Level Fuel Remaining - Gal (L)
Empty 75-80 13-15% 0-3.9 (0-14.7)
1/4 123 35% 9.0 (34)
1/2 159 53% 14.0 (53)
3/4 196 75% 20.0 (75.7)
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