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Home >> Oldsmobile >> 1997 >> Achieva SC, 2.4 T, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Engine Testing - 2.4L >> On-Board Diagnostic (OBD) System Check >> DLC Diagnosis Or No Scan Tool Data
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DLC Diagnosis Or No Scan Tool Data

  1. Perform On-Board Diagnostic (OBD) System Check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . After performing OBD system check, go to next step.
  2. Turn ignition on with engine off. Install scan tool. If scan tool is equipped with external power source, ensure power source and ground are okay. If scan tool powers up, go to next step. If scan tool does not power up, go to step 4).
  3. Disconnect scan tool. Using a test light connected to ground, probe DLC class 2 serial data circuit. See the WIRING DIAGRAMS article. If test light does not illuminate, go to step 5). If test light illuminates, go to step 6).
  4. Using a test light connected to ground, probe DLC battery feed circuit. See the WIRING DIAGRAMS article. If test light illuminates, go to step 7). If test light does illuminate, go to step 8).
  5. Using a test light connected to battery voltage, probe DLC class 2 serial data circuit. See the WIRING DIAGRAMS article. If test light does not illuminate, go to step 9). If test light does illuminate, go to step 10).
  6. Check for short to voltage in class 2 serial data circuit. Repair as necessary. After repairs, go to step 17). If circuit is okay, go to step 11).
  7. Using a test light connected to battery voltage, probe DLC ground circuits. See the WIRING DIAGRAMS article. If test light illuminates for both ground circuits, go to step 15). If test light does not illuminate for both ground circuits, go to step 12).
  8. Repair open or short to ground in DLC battery feed circuit. After repairs, go to step 17).
  9. Check for open or poor connection in class 2 serial data circuit. Repair as necessary. After repairs, go to step 17). If circuit is okay, go to step 13).
  10. Check for short to ground in class 2 serial data circuit. Repair as necessary. After repairs, go to step 17). If circuit is okay, go to next step.
  11. Replace PCM. Perform PCM relearn procedures. After repairs, go to step 17).
  12. Repair open or poor connections in DLC ground circuits. After repairs, go to step 17).
  13. Reinstall scan tool. If scan tool can communicate with PCM, go to step 17). If scan tool can not communicate with PCM, go to next step.
  14. Install scan tool on another vehicle equipped with class 2 serial data and check for proper operation. If scan tool operates properly, go to step 11). If scan tool does not operate properly, go to step 16).
  15. Check DLC for proper terminal tension or excessive resistance. Repair as necessary. After repairs, go to step 17). If terminals are okay, go to next step.
  16. Scan tool is malfunctioning. Using scan tool operation manual, repair as necessary. After repairs, go to step 17).
  17. Using scan tool, clear DTCs. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and then dies, go to step 1).
  18. Warm engine to operating temperature. Check for DTCs. If DTCs are present, diagnose DTCs. See the TESTS W/CODES article. If DTCs are not present, system is okay.
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