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Scan Tool Does Not Communicate With Class 2 Device In Data Link Communications

  1. Install scan tool. If scan tool powers up, go to next step. If scan tool does not power up, check DLC circuit. See WIRING DIAGRAMS .
  2. Turn ignition on, with engine off. Using scan tool, attempt to communicate with each module on the class 2 serial data circuit. If scan tool communicates with any module on the serial data circuit, go to next step. If scan does not communicate with any module on the serial data circuit, go to step  5.
  3. Using scan tool, select DTCs function for each module. Record all displayed DTCs, DTC status and module that set the DTC. If any DTCs recorded are in the range of DTC U1000-U1255, go to next step. If no DTCs are recorded, problem is intermittent. See INTERMITTENTS & POOR CONNECTIONS .
  4. If only DTC U1000 is present, diagnose DTC U1000. See DTC U1000 & U1255: CLASS 2 COMMUNICATION MALFUNCTION  under DIAGNOSTIC TESTS. If DTC U1000 is not present, problem is intermittent.
  5. Turn ignition off. Disconnect scan tool from DLC. Check for poor terminal connection or tension at DLC terminals No. 2 and 5. Repair as necessary. After repairs, go to next step. If no problem is found, go to step  17.
  6. Check for open in DCL ground circuit, DLC terminal No. 5. See WIRING DIAGRAMS . Repair as necessary. After repairs, go to step  17. If ground circuit is okay, go to next step.
  7. Disconnect left instrument panel junction block connector C1. Check for poor connections or terminal tension at connector. Repair as necessary. After repairs, go to step  17. If connector is okay, go to next step.
  8. Check class 2 serial data circuit for open or short circuit between DLC terminal No. 2 and junction block connector terminal D2. See WIRING DIAGRAMS . Repair as necessary. After repairs, go to step  17. If circuit is okay, go to next step.
  9. Check for open or short in circuit between left instrument panel junction block connector C1 and connectors A3, D2 and E3. See WIRING DIAGRAMS . Repair as necessary. After repairs, go to step  17. If circuit is okay, go to next step.
  10. Turn ignition off. Disconnect BCM harness connector. Turn ignition on, with engine off. Check for short to ground or short to voltage in class 2 serial data circuit between BCM and left instrument panel junction block connector. See WIRING DIAGRAMS . Repair as necessary. After repairs, go to step  17. If circuit is okay, go to next step.
  11. Turn ignition off. Disconnect inflatable restraint Sensing and Diagnostic Module (SDM) harness connector. Turn ignition on, with engine off. Check for short to ground or short to voltage in class 2 serial data between SDM and left instrument panel junction block connector. See WIRING DIAGRAMS . Repair as necessary. After repairs, go to step  17. If circuit is okay, go to next step.
  12. Turn ignition off. Disconnect EBCM harness connector. Turn ignition on, with engine off. Check for short to ground or short to voltage in class 2 serial data between EBCM and left instrument panel junction block connector. See WIRING DIAGRAMS . Repair as necessary. After repairs, go to step  17. If circuit is okay, go to next step.
  13. Turn ignition off. Disconnect PCM harness connector. Turn ignition on, with engine off. Check for short to ground or short to voltage in class 2 serial data between PCM and left instrument panel junction block connector. See WIRING DIAGRAMS . Repair as necessary. After repairs, go to step  17. If circuit is okay, go to next step.
  14. Turn ignition off. Disconnect instrument panel cluster harness connector. Turn ignition on, with engine off. Check for short to ground or short to voltage in class 2 serial data between instrument panel cluster and left instrument panel junction block connector. See WIRING DIAGRAMS . Repair as necessary. After repairs, go to step  17. If circuit is okay, go to next step.
  15. Check for poor connection or terminal tension at Class serial data circuit of each module that is not communicating. Repair as necessary. After repairs, go to step  17. If connectors and terminals are okay, go to next step.
  16. Replace module that is not communicating. After replacing faulty module, go to next step.
  17. Reconnect all disconnected modules and connectors. Install scan tool. Turn ignition on, with engine off. Wait 10 seconds for scan tool to perform power up reset. Using scan tool, select DISPLAY DTC function. Record all displayed DTCs and DTC status. Diagnose affected DTC(s), then clear DTC(s). If no DTC(s) are recorded, system is okay.
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