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Home >> Saturn >> 2000 >> SW2 Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Testing & Engine Component Testing >> Engine Sensors & Switches >> Engine Oil Level Switch >> 3.1L, 3.4L & 3.8L
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3.1L, 3.4L & 3.8L

  1. Using scan tool, observe engine oil level display. If scan tool does not display OK, go to next step. If scan tool displays OK, check the following:
    • Poor connections at engine oil level switch and PCM. Check for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connection.
    • Inspect wiring harness for damage. If harness is okay, disconnect PCM and turn ignition on. Connect DVOM to affected PCM output circuit. Wiggle connectors and wiring harnesses related to PCM output circuit. A change in voltage will indicate location of fault.
    • On 3.1L and 3.8L, if fault in oil level indicator cannot be isolated using engine oil level switch diagnosis, perform PCM controlled warning light diagnosis. See PCM CONTROLLED WARNING LIGHTS  under MISCELLANEOUS CONTROLS.
  2. Turn ignition off. Disconnect PCM harness connector C2. Using a test light connected to battery voltage, probe engine oil level switch signal circuit (Brown wire) at PCM harness connector. If test light does not illuminate, go to next step. If test light illuminates, go to step  6.
  3. Turn ignition off. Reconnect PCM harness connector. Turn ignition on. Raise and support vehicle. Disconnect engine oil level switch harness connector. Using DVOM, measure voltage between engine oil level switch harness connector terminals. If battery voltage is not present, go to next step. If battery voltage is present, go to step  7.
  4. Using DVOM, measure voltage between engine oil level switch harness connector signal circuit (Brown wire) and chassis ground. If battery voltage is not present, go to next step. If battery voltage is present, go to step  8.
  5. Check for an open in engine oil level switch signal circuit (Brown wire). If problem exists, repair as necessary and go to step  11. If problem does not exist, check the following:
    • Poor connections at engine oil level switch and PCM. Check for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connection.
    • Inspect wiring harness for damage. If harness is okay, disconnect PCM and turn ignition on. Connect DVOM to affected PCM output circuit. Wiggle connectors and wiring harnesses related to PCM output circuit. A change in voltage will indicate location of fault.
    • On 3.1L and 3.8L, if fault in oil level indicator can not be isolated using engine oil level switch diagnosis, perform PCM controlled warning light diagnosis. See PCM CONTROLLED WARNING LIGHTS  under MISCELLANEOUS CONTROLS.
  6. Check for poor connections at PCM. If problem exists, repair as necessary and go to step  11. If problem does not exist, go to step  10.
  7. Check for poor connections at engine oil level switch. If problem exists, repair as necessary and go to step  11. If problem does not exist, go to step  9.
  8. Locate and repair open in engine oil level switch ground circuit (Black/White wire). After repairs, go to step  11.
  9. Replace engine oil level switch. After repairs, go to step  11.
  10. Replace PCM. After repairs, go to next step.
  11. Start engine and allow to warm to normal operating temperature. Turn ignition off and allow engine to cool for 15 minutes. Turn ignition on. Using scan tool, observe engine oil level display. If scan tool displays OK, system is okay. If scan tool does not display OK, go to step  2.
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