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HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 23 (ANALOG INSTRUMENT PANELS)SYSTEM TESTSTEST L: LOW ENG OIL LEVEL MESSAGE IS ALWAYS ON
1999 GMC Forward Control 5.7 R, Automatic

Test L: Low Eng Oil Level Message Is Always On

1999 GMC Forward Control 5.7 R, AutomaticSECTION Test L: Low Eng Oil Level Message Is Always On
WARNING: This page is about a different car, the 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, 2001 Chevrolet Monte Carlo, and 2001 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform instrument panel cluster system diagnostic system check. See INSTRUMENT PANEL CLUSTER SYSTEM DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. If instrument panel cluster system diagnostic system check has been performed, go to next step.
  2. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to RUN position. Using scan tool, observe ENGINE OIL LEVEL SWITCH parameter in PCM ENGINE data list. If scan tool displays OK, go to next step. If scan tool does not display OK, go to step  4 .
  3. Check for LOW ENG OIL LEVEL message in message center. If LOW ENG OIL LEVEL message is indicated, go to step  11 . If LOW ENG OIL LEVEL message is not indicated, check for intermittent problem. See DIAGNOSING INTERMITTENTS  . Repair or replace as necessary. After repair, go to step  12 .
  4. Turn ignition switch to OFF position. Disconnect engine oil level switch connector from oil pan. Connect a 3-amp fused jumper wire between ground and engine oil level switch harness connector terminal "A" (Brown wire). Turn ignition switch to RUN position. Using scan tool, observe ENGINE OIL LEVEL SWITCH parameter in PCM ENGINE data list. If ENGINE OIL LEVEL SWITCH parameter displays LOW, go to step  6 . If ENGINE OIL LEVEL SWITCH parameter does not display LOW, go to next step.
  5. Check for open, high resistance or short to voltage in Brown wire between engine oil level switch connector terminal "A" and PCM Clear 80-pin connector C2 terminal No. 58. See Figure . Repair as necessary and go to step  12 . See WIRING DIAGRAMS  . If wire is okay, go to step  8 .
  6. Check for open or high resistance in Black wire between engine oil level switch connector terminal "B" and ground connector G113. See Figure . Repair as necessary and go to step  12 . See WIRING DIAGRAMS  . If wire is okay, go to next step.
  7. Check for poor connection at engine oil level switch connector. Repair as necessary and go to step  12 . If connection is okay, go to step  9 .
  8. Disconnect PCM Clear 80-pin connector C2. Check for poor connection at PCM Clear 80-pin connector C2. Repair as necessary and go to step  12 . If connection is okay, go to step  10 .
  9. Replace engine oil level switch. After repair, go to step  12 .
  10. Replace and reprogram PCM. See BODY CONTROL MODULES - IMPALA & MONTE CARLO article. After repair, go to step  12 .
  11. Replace IPC. See INSTRUMENT PANEL CLUSTER (IPC)  under REMOVAL & INSTALLATION. After repair, go to next step.
  12. Check LOW ENG OIL LEVEL message operation. If system operates normally, repair is complete. If problem still exists, return to step  2 .
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.