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Scan Tool Does Not Communicate With Class 2 Device: Testing: Notes

  1. Connect scan tool to Data Link Connector (DLC). If scan tool does not power up, go to SCAN TOOL DOES NOT POWER UP . If scan tool powers up, go to next step.
  2. Turn ignition on. Attempt to communicate with each module on class 2 serial data line. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. If scan tool communicates with one or modules, go to next step. If scan tool does not communicate with any module, go to step  5.
  3. Select Display DTCs function for each module. Record all DTCs, DTC status and which module set the DTC(s). If any DTCs between DTC U1000 and U1255 are set, go to next step. If no DTCs between DTC U1000 and U1255 are set, go to DIAGNOSTIC AIDS .
  4. If only DTC U1000 or U1255 is set, go to DTC U1000 OR U1255: CLASS 2 COMMUNICATION MALFUNCTION  under DIAGNOSTIC TESTS. If other DTC(s) between DTC U1000 and U1255 are set, go to DTC U1001-U1254: LOSS OF XXX COMMUNICATION  under DIAGNOSTIC TESTS.
  5. Turn ignition off. Disconnect scan tool from DLC. Inspect DLC terminals No. 2 and 5 for poor connections. See Figure. Repair connector as necessary. Perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If connector is okay, go to next step.
  6. Check for open in ground circuit between DLC terminal No. 5 (Black/White wire) and ground. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. Repair circuit as necessary. Perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If circuit is okay, go to next step.
  7. Disconnect splice pack SP205. Inspect splice pack SP205 for poor connections. Repair splice pack as necessary and perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If splice pack is okay, go to next step.
  8. Check for open or short in class 2 serial data line (Purple wire) between DLC terminal No. 2 and splice pack SP205 terminal "A". See Figure. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. Repair circuit as necessary and perform appropriate diagnostic system check. See appropriate article for malfunctioning system. If circuit is okay, go to next step.
  9. Using Connector Adapter Kit (J35616-A), connect a jumper wire between splice pack SP205 terminals "A" (Purple wire) and "M" (Light Green wire). Turn ignition on. Attempt to communicate with BCM. If scan tool communicates with BCM, go to step  11. If scan tool does not communicate with BCM, go to next step.
  10. Turn ignition off. Disconnect Brown BCM harness connector. Check for short to ground or voltage in class 2 serial data line (Light Green wire) between splice pack SP205 terminal "M" and BCM harness connector C1 terminal A12. See Figure. Repair circuit as necessary and go to step  28. If circuit is okay, go to step  26.
  11. Turn ignition off. Connect another jumper wire between jumper wire connected to splice pack SP205 terminal "A" and splice pack SP205 terminal "B" (Dark Green wire). Turn ignition on. Attempt to communicate with Powertrain Control Module (PCM) or Vehicle Control Module (VCM). If scan tool communicates with PCM or VCM, go to step  13. If scan tool does not communicate with PCM or VCM, go to next step.
  12. Turn ignition off. Disconnect PCM/VCM harness connectors. Check for short to ground or voltage in class 2 serial data line (Dark Green wire) between splice pack SP205 terminal "B" and VCM harness connector C4 terminal No. 11 (4.3L engine) or PCM harness connector C1 terminal No. 58 (all other gas engines). Repair circuit as necessary and go to step  28. If circuit is okay, go to step  26.
  13. Turn ignition off. Move jumper wire from splice pack SP205 terminal "B" to terminal "C" (Dark Green/White wire). Turn ignition on. Attempt to communicate with Automatic Transfer Case (ATC) module. If scan tool communicates with ATC module, go to step  15. If scan tool does not communicate with ATC module, go to next step.
  14. Turn ignition off. Disconnect ATC module harness connectors. Check for short to ground or voltage in class 2 serial data line (Dark Green/White wire) between splice pack SP205 terminal "C" and ATC module harness connector C1 terminal E9. Repair circuit as necessary and go to step  28. If circuit is okay, go to step  26.
  15. Turn ignition off. Move jumper wire from splice pack SP205 terminal "C" to terminal "E" (Light Blue wire). Turn ignition on. Attempt to communicate with Electronic Brake Control Module (EBCM). If scan tool communicates with EBCM, go to step  17. If scan tool does not communicate with EBCM, go to next step.
  16. Turn ignition off. Disconnect EBCM harness connectors. Check for short to ground or voltage in class 2 serial data line (Light Blue wire) between splice pack SP205 terminal "E" and EBCM harness connector C2 terminal B6. Repair circuit as necessary and go to step  28. If circuit is okay, go to step  26.
  17. Turn ignition off. Move jumper wire from splice pack SP205 terminal "E" to terminal "F" (Dark Blue wire). Turn ignition on. Attempt to communicate with inflatable restraint Sensing and Diagnostic Module (SDM). If scan tool communicates with SDM, go to step  19. If scan tool does not communicate with SDM, go to next step.
  18. Turn ignition off. Disconnect SDM harness connectors. Check for short to ground or voltage in class 2 serial data line (Dark Blue wire) between splice pack SP205 terminal "F" and SDM harness connector C1 terminal A4. Repair circuit as necessary and go to step  28. If circuit is okay, go to step  26.
  19. Turn ignition off. Move jumper wire from splice pack SP205 terminal "F" to terminal "G" (Gray wire). Turn ignition on. Attempt to communicate with Instrument Panel Cluster (IPC) If scan tool communicates with IPC, go to step  21. If scan tool does not communicate with IPC, go to next step.
  20. Turn ignition off. Disconnect IPC harness connector. Check for short to ground or voltage in class 2 serial data line (Gray wire) between splice pack SP205 terminal "G" and IPC harness connector terminal A5. Repair circuit as necessary and go to step  28. If circuit is okay, go to step  26.
  21. Turn ignition off. Move jumper wire from splice pack SP205 terminal "G" to terminal "H" (Dark Blue/White wire). Turn ignition on. Attempt to communicate with Suspension Control Module (SCM). If scan tool communicates with SCM, go to step  23. If scan tool does not communicate with SCM, go to next step.
  22. Turn ignition off. Disconnect SCM harness connectors. Check for short to ground or voltage in class 2 serial data line (Dark Blue/White wire) between splice pack SP205 terminal "H" and SCM harness connector C2 terminal B8. Repair circuit as necessary and go to step  28. If circuit is okay, go to step  26.
  23. Turn ignition off. Move jumper wire from splice pack SP205 terminal "H" to terminal "L" (White wire). Turn ignition on. Attempt to communicate with Heating, Ventilation & Air Conditioning (HVAC) control module. If scan tool communicates with HVAC control module, go to step  25. If scan tool does not communicate with HVAC control module, go to next step.
  24. Turn ignition off. Disconnect HVAC control module harness connector. Check for short to ground or voltage in class 2 serial data line (White wire) between splice pack SP205 terminal "L" and HVAC control module harness connector terminal C11. Repair circuit as necessary and go to step  28. If circuit is okay, go to step  26.
  25. Turn ignition off. Check for short to ground or voltage in class 2 serial data line (Orange wire) between splice pack SP205 terminal "D" and cellular phone ready wiring at body wiring harness junction block harness connector C1 terminal A2. Repair circuit as necessary and go to step  28. If circuit is okay, go to DIAGNOSTIC AIDS .
  26. Inspect harness connector of non-communicating module for poor connections. Repair connector as necessary and go to step  28. If connector is okay, go to next step.
  27. Replace non-communicating module. See appropriate procedure under REMOVAL & INSTALLATION. Go to next step.
  28. Reconnect all harness connectors. Connect scan tool to DLC. Turn ignition on. Wait 10 seconds. Scan tool may require a power up reset before communication will occur. Turn ignition off and disconnect scan tool. Reconnect scan tool and turn ignition on. Display DTCs for each module. Record DTC(s) and DTC status. If any current DTCs that begin with a "U" are present, go to step  30. If no current DTCs that begin with a "U" are present, go to next step.
  29. If any DTCs that do not begin with a "U" are present, go to next step. If no DTCs that do not begin with a "U" are present, go to step  32.
  30. Perform appropriate diagnostic procedure for DTC(s) present. See appropriate article for malfunctioning system. After repairs, go to next step.
  31. If all DTCs have been diagnosed, go to next step. If any DTCs have not been diagnosed, go to step  30.
  32. Using scan tool, clear DTCs. System is okay.
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