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Home >> Chevrolet >> 1997 >> Camaro Z28, 2D Convertible, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Basic Engine Testing - 5.7L >> 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 powers up, go to next step. If scan tool does not power up, go to step 10).
  3. If engine starts and continues to run, go to step 15). If engine does not start, or starts and then dies, go to next step.
  4. Turn ignition off. Disconnect PCM connector. Using a test light connected to ground, probe PCM battery feed circuit and ignition feed circuit. See the WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 7).
  5. Using DVOM, measure resistance between chassis ground and PCM ground circuits. See the WIRING DIAGRAMS article. DVOM should read 5 ohms or less for each circuit. If resistance is as specified, go to next step. If resistance is not as specified, go to step 8).
  6. Check for poor PCM connections. Repair as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If connections are okay, go to step 9).
  7. Repair circuit that did not illuminate test light. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  8. Repair faulty PCM ground circuits. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  9. Replace PCM. Perform PCM relearn procedures. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  10. Disconnect scan tool. Using a test light connected to ground, probe DLC battery feed circuit. See the WIRING DIAGRAMS article. If test light does not illuminate, go to step 12). If test light illuminates, go to next step.
  11. Using DVOM, measure resistance between chassis ground and DLC ground circuits. See the WIRING DIAGRAMS article. DVOM should read 5 ohms or less for each circuit. If resistance is as specified, go to step 14). If resistance is not as specified, go to step 13).
  12. Repair DLC battery feed circuit. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  13. Repair DLC ground circuits. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  14. Replace faulty scan tool. After scan tool replacement, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  15. Using DVOM, measure resistance between chassis ground and DLC ground circuits. See the WIRING DIAGRAMS article. DVOM should read 5 ohms or less for each circuit. If resistance is as specified, go to next step. If resistance is not as specified, go to step 17).
  16. Check for open, short to voltage or short to ground in class 2 serial data circuit. Repair as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If circuit is okay, go to step 18).
  17. Repair DLC ground circuits. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  18. Install scan tool on another vehicle and check for proper operation. If scan tool operates properly, go to next step. If scan tool does not operate properly, go to step 20).
  19. Replace PCM. Perform PCM relearn procedures. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  20. Replace faulty scan tool. After scan tool replacement, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
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