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Home >> Cadillac >> 1998 >> Catera >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes >> Self-Diagnostic System >> DLC Diagnosis Or No Scan Tool Data
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DLC Diagnosis Or No Scan Tool Data

  1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  , then 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 9).
  3. If engine starts and continues to run, go to step 12). If engine does not start, or starts and then dies, go to next step.
  4. Turn ignition off. Disconnect ECM connector. Using a test light connected to ground, probe ECM ignition feed circuit. See WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 6).
  5. Using a test light connected to battery voltage, probe ECM ground circuits. See WIRING DIAGRAMS article. If test light illuminates on all ground circuits, go to step 16). If test light does not illuminate on all ground circuits, go to step 7).
  6. Repair ignition feed circuit. After repairs, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  7. Repair open or high resistance in affected circuit. After repairs, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  8. Repair short to ground in affected circuit. After repairs, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  9. Disconnect scan tool. Using a test light connected to ground, probe DLC battery feed circuit. See WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 11).
  10. Using a test light connected to battery voltage, probe DLC ground circuits. See WIRING DIAGRAMS article. If test light illuminates for both ground circuits, go to step 18). If test light does not illuminate for both ground circuits, go to step 14).
  11. Repair DLC battery feed circuit. After repairs, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  12. Disconnect scan tool. Using a test light connected to battery voltage, probe DLC ground circuits. See WIRING DIAGRAMS article. If test light illuminates for both ground circuits, go to next step. If test light does not illuminate for both ground circuits, go to step 14).
  13. Check for open, short to ground or short to voltage in serial data circuit. Repair as necessary. After repairs, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If circuit is okay, go to step 15).
  14. Repair open or high resistance in DLC ground circuits. After repairs, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  15. 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 18).
  16. Check ECM for proper terminal tension or poor connection. Repair as necessary. After repairs, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If terminals and connection are okay, go to next step.
  17. Replace ECM. Perform ECM relearn procedures. After repairs, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  18. Replace faulty scan tool. After scan tool replacement, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
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