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Scan Tool Does Not Communicate With Class 2 Serial Data Line

NOTE: To identify components on class 2 serial data line, see appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS.
  1. Perform DATA LINK CONNECTOR DIAGNOSTIC SYSTEM CHECK  . Go to next step.
  2. Connect scan tool to another vehicle of same model year to ensure proper operation of scan tool. If scan tool cannot communicate with another vehicle, go to next step. If scan tool can communicate with another vehicle, go to step  4 .
  3. Scan tool may be defective. Refer to scan tool manufacture's instructions. If scan tool is operating properly, go to step  33 .
  4. Turn ignition switch to OFF position. Connect scan tool to original vehicle. Ensure connections of Data Link Connector (DLC) are clean and tight. DLC is located under instrument panel, left of steering column. Check for any terminals that are not seated properly. If faulty connections are found, go to next step. If connections are okay, go to step  6 .
  5. Repair faulty terminals. After repairs, go to step  33 .
  6. Turn ignition switch to RUN position, with engine off. If scan tool will turn on, go to step  12 . If scan tool will not turn on, go to next step.
  7. Using DVOM, measure voltage between DLC connector terminal No. 16 (Orange wire) and ground. If battery voltage exists, go to step  9 . If battery voltage does not exist, go to next step.
  8. Repair open or short to ground in Orange wire between DLC connector and I/P junction block Gray 68-pin connector C1. After repairs, go to step  33 .
  9. Measure voltage between DLC terminals No. 16 (Orange wire) and No. 5 (Black/White wire). If battery voltage exists, go to step  11 . If battery voltage does not exist, go to next step.
  10. Repair open in Black/White wire between DLC connector terminal No. 5 and ground. After repairs, go to step  33 .
  11. Repair open in Black wire between DLC connector terminal No. 4 and ground. After repairs, go to step  33 .
  12. Using DVOM, measure voltage between DLC connector terminal No. 2 (Purple wire) and ground. If battery voltage exists, go to step  15 . If battery voltage does not exist, go to next step.
  13. Using DVOM, measure resistance between DLC connector terminal No. 2 (Purple wire) and ground. If resistance is 0-5 ohms, go to step  24 . If resistance is not 0-5 ohms, go to next step.
  14. Repair open in Purple wire between DLC connector and Gray 16-pin connector C200 terminal "A". C200 is located in body-to-instrument panel harness under left side of instrument panel, to left of steering column. After repairs, go to step  33 .
  15. Disconnect 24-pin connector C206. C206 is located in instrument panel-to-steering column harness above steering column. Using DVOM, measure voltage between DLC connector terminal No. 2 (Purple wire) and ground. If battery voltage exists, go to step  17 . If battery voltage does not exist, go to next step.
  16. Repair short to battery voltage in Purple wires between connector C206 terminals B5 and B6. After repairs, go to step  33 .
  17. Disconnect Blue, 24-pin connector C310. C310 is located in body-to-rear shelf harness in right front of rear compartment. Using DVOM, measure voltage between DLC connector terminal No. 2 (Purple wire) and ground. If battery voltage exists, go to next step. If battery voltage does not exist, go to step  19 .
  18. Repair short to battery voltage in Purple wire between connector C206 terminal B5 and connector C310 terminal A3. After repairs, go to step  33 .
  19. Reconnect connector C310. Disconnect I/P junction block Brown, 68-pin connector C4. Using DVOM, measure voltage between DLC connector terminal No. 2 (Purple wire) and ground. If battery voltage exists, go to next step. If battery voltage does not exist, go to step  21 .
  20. Repair short to battery voltage in Purple wire between I/P junction block connector C4 terminal F1 and connector C310 terminal A3. After repairs, go to step  33 .
  21. Reconnect connector C206. Using DVOM, measure voltage between DLC connector terminal No. 2 (Purple wire) and ground. If battery voltage exists, go to next step. If battery voltage does not exist, go to step  23 .
  22. Check for short to battery voltage in Purple wire between I/P junction block connector C4 terminal D12 and connector C206 terminal B6. Check for internal short to battery voltage in I/P junction block. Replace I/P junction block if necessary. After repairs, go to step  33 .
  23. Repair short to battery voltage in Purple wires between I/P junction block connector C4 terminals D1 and E1. After repairs, go to step  33 .
  24. Disconnect 24-pin connector C206. Using DVOM, measure resistance between DLC connector terminal No. 2 (Purple wire) and ground. If resistance is 0-5 ohms, go to step  26 . If resistance is not 0-5 ohms, go to next step.
  25. Repair short to ground in Purple wires between connector C206 terminals B5 and B6. After repairs, go to step  33 .
  26. Disconnect Blue, 24-pin connector C310. Using DVOM, measure resistance between DLC connector terminal No. 2 (Purple wire) and ground. If resistance is 0-5 ohms, go to step  28 . If resistance is not 0-5 ohms, go to next step.
  27. Repair short to ground in Purple wire between connector C206 terminal B5 and connector C310 terminal A3. After repairs, go to step  33 .
  28. Reconnect connector C310. Disconnect I/P junction block Brown 68-pin connector C4. Using DVOM, measure resistance between DLC connector terminal No. 2 (Purple wire) and ground. If resistance is 5 ohms or less, go to step  30 . If resistance is not 5 ohms or less, go to next step.
  29. Repair short to ground in Purple wire between I/P junction block connector C4 terminal F1 and connector C310 terminal A3. After repairs, go to step  33 .
  30. Reconnect connector C206. Using DVOM, measure resistance between DLC connector terminal No. 2 (Purple wire) and ground. If resistance is 5 ohms or less, go to next step. If resistance is not 5 ohms or less, go to step  32 .
  31. Check for short to ground in Purple wire between I/P junction block connector C4 terminal D12 and connector C206 terminal B6. Check for internal short to ground in I/P junction block. Repair as necessary. After repairs, go to step  33 .
  32. Repair short to ground in Purple wires between I/P junction block connector C4 terminals D1 and E1. After repairs, go to next step.
  33. Turn ignition off. Reconnect all disconnected components and connectors. Turn ignition on. Clear DTCs. Go to DATA LINK CONNECTOR DIAGNOSTIC SYSTEM CHECK  .
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