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Home >> Oldsmobile >> 1997 >> Aurora >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Testing 4.0L >> On-Board Diagnostic (OBD) System Check >> DLC Diagnosis Or No Scan Tool Data

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. Check all PCM power and ground connections and circuits. Repair as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If connections and circuits are okay, go to next step.
  3. Ensure battery is fully charged. Using DVOM, measure voltage between DLC battery feed circuit and DLC ground circuits. See the WIRING DIAGRAMS article. Voltage reading for both circuits should be 10 volts. If voltage readings are the same or higher for both circuits, go to step 7). If voltage readings are not the same or higher for both circuits, go to next step.
  4. Using DVOM, measure voltage between ground and DLC battery feed circuit. See the WIRING DIAGRAMS article. Voltage reading should be 10 volts. If voltage is as specified, go to next step. If voltage is not as specified, go to step 6).
  5. Repair open in DLC ground circuit that had low or no voltage. After repairs, go to step 7).
  6. Repair open or short to ground in DLC battery feed circuit. Replace blown fuse as necessary. After repairs, go to next step.
  7. Turn ignition on. If scan tool displays PCM data, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If scan tool does not display PCM data, go to next step.
  8. 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 13).
  9. Reinstall scan tool on original vehicle and enter fluid life information. Turn ignition off and wait 30 seconds. Disconnect PCM connector C1. Using DVOM, measure resistance of class 2 serial data circuit between PCM and DLC. See the WIRING DIAGRAMS article. If resistance is more than 5 ohms, go to step 11). If resistance is less than 5 ohms, go to next step.
  10. Disconnect Remote Accessory Control (RAC) module connector. Using DVOM, measure resistance of DLC class 2 serial data circuit to ground. See the WIRING DIAGRAMS article. If resistance is less than 10,000 ohms, go to step 12). If resistance is more than 10,000 ohms, go to step 14).
  11. Repair open in class 2 serial data circuit. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  12. Repair short to ground in class 2 serial data circuit. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  13. Replace faulty scan tool. After scan tool replacement, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  14. Reconnect PCM connector. Check for PCM data with RAC module disconnected. If scan tool displays PCM data, go to step 17). If scan tool does not display PCM data, go to next step.
  15. Check PCM connections at connector C1. Repair as necessary. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . If connections are okay, go to next step.
  16. Replace PCM. Perform PCM relearn procedures. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
  17. Replace RAC module. After repairs, perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  .
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