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Home >> Oldsmobile >> 1998 >> LSS 3.8 1 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Engine Sensors & Switches >> Engine Controls - System/Component Tests >> Fuel Level Sensor Diagnosis
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Fuel Level Sensor Diagnosis

  1. If powertrain OBD system check has been performed, go to next step. If powertrain OBD system check has not been performed, perform powertrain OBD system check. See POWERTRAIN OBD SYSTEM CHECK in TESTS W/CODES article.
  2. Retrieve instrument panel-related DTCs. If no instrument panel DTCs exist, go to next step. If any instrument panel DTCs exist, perform appropriate DTC test. See TESTS W/CODES article.
  3. Connect scan tool to data link connector. Turn ignition switch to RUN position. Using scan tool output control function, perform FUEL GAUGE SWEEP TEST. If fuel gauge sweeps through full range, go to next step. If fuel gauge does not sweep through full range, repair fuel gauge. See INSTRUMENT PANEL article in ACCESSORIES/SAFETY EQUIPMENT section.
  4. Turn ignition switch to LOCK position. Raise and support vehicle. Disconnect fuel tank harness connector. Connect voltmeter between fuel level sensor input circuit (Purple wire) and fuel level sensor ground circuit (Black/White wire) at fuel level sensor harness connector. Turn ignition switch to RUN position. If voltage does not exist, go to next step. If voltage exists, go to step 6).
  5. Check fuel level sensor input and ground circuit for open between fuel level sensor and PCM. If open does not exist, go to step 10). If open exists, repair as necessary and go to step 13).
  6. If greater than 5 volts existed in step 4), go to step 11). If 5 volts or less existed in step 4), go to next step.
  7. Measure voltage between fuel level sensor input circuit (Purple wire) and ground. If approximately 5 volts exists, go to next step. If approximately 5 volts does not exist, go to step 9).
  8. Locate and repair open in fuel level sensor ground circuit (Black/White wire). After repairs are complete, go to step 13).
  9. Check fuel level sensor input circuit (Purple wire) for open or short to ground. If problem does not exist, go to step 11). If problem exists, repair as necessary and go to step 13).
  10. Replace fuel level sensor and go to step 13).
  11. Locate and repair short to voltage in fuel level sensor input circuit (Purple wire). After repairs are complete, go to step 13).
  12. Replace PCM and go to next step.
  13. Recheck system for proper operation. If system is not operating properly, go to step 2).
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