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Scan Tool Does Not Communicate With Class 2 Serial Data Line

  1. If DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK has been performed, go to next step. If DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK has not been performed, go to DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK  then go to next step.
  2. Connect scan tool to another 1999 model year vehicle to ensure proper operation of scan tool. If scan tool operates on another vehicle, go to step  4 . If scan tool does not operate, go to next step.
  3. Repair scan tool. Refer to scan tool manufacture's instructions for proper operation. After repairing scan tool, go to DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK  .
  4. Connect scan tool to malfunctioning vehicle. Check connections between Data Link Connector (DLC) and scan tool connector. If connections are okay, go to step  6 . If connections are faulty, go to next step.
  5. Repair terminal contact between DLC and scan tool. After repairs, go to step  71 .
  6. Turn ignition switch to ON position. If scan tool powers up, go to step  13 . If scan tool does not power up, go to next step.
  7. Using DVOM, measure voltage between ground and DLC terminal No. 16 (Orange wire). See WIRING DIAGRAMS  . If reading is 10-15 volts, go to step  9 . If reading is not 10-15 volts, go to next step.
  8. Repair open or short to ground in Orange wire between rear junction block and DLC. After repairs, go to step  71 .
  9. Using DVOM, measure voltage between DLC terminals No. 16 (Orange wire) and No. 5 (Black/White wire). If reading is 10-15 volts, go to step  11 . If reading is not 10-15 volts, go to next step.
  10. Repair open in Black/White wire between ground and DLC. After repairs, go to step  71 .
  11. Using DVOM, measure voltage between DLC terminals No. 16 (Orange wire) and No. 4 (Black wire). If reading is 10-15 volts, go to DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK  . If reading is not 10-15 volts, go to next step.
  12. Repair open in Black wire between ground and DLC. After repairs, go to step  71 .
  13. Disconnect PCM connectors. Attempt to communicate with Dash Integration Module (DIM). If scan tool communicates, go to next step. If scan tool does not communicate, go to step  15 .
  14. Replace PCM. See REMOVAL, OVERHAUL & INSTALLATION - CARS article in ENGINE PERFORMANCE. After replacement, go to step  71 .
  15. Disconnect EBTCM connectors. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  18 .
  16. Check for short to ground or short to battery voltage in Purple wire between EBTCM connector terminal No. 10 and PCM connector C1 terminal No. 59. If short was found, go to step  70 . If circuit is okay, go to next step.
  17. Replace EBTCM. See appropriate ANTI-LOCK article in BRAKES. Replace PCM. See REMOVAL, OVERHAUL & INSTALLATION - CARS article in ENGINE PERFORMANCE. After replacement, go to step  71 .
  18. If vehicle is equipped with A45 (memory personalization package), go to next step. If vehicle is not equipped with A45 (memory personalization package), go to step  21 .
  19. Disconnect Memory Seat Module (MSM) connector. Module is located under driver's seat. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  21 .
  20. Replace MSM. See POWER SEATS - SEVILLE article. After replacement, go to step  71 .
  21. If vehicle is equipped with factory cellular telephone, go to next step. If vehicle is not equipped with factory cellular telephone, go to step  24 .
  22. Disconnect cellular telephone module connector. Module is located in trunk on electronic bay board. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  24 .
  23. Replace cellular telephone module. After replacement, go to step  71 .
  24. Disconnect Instrument Panel Cluster (IPC) connector. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  27 .
  25. Check for short to ground or short to battery voltage in Purple wire between IPC connector C2 terminal B8 and EBTCM connector terminal No. 26. If short was found, go to step  70 . If circuit is okay, go to next step.
  26. Replace IPC. See ANALOG INSTRUMENT PANELS - SEVILLE article. After replacement, go to step  71 .
  27. Disconnect theft deterrent module connector. Module is located on right side of the instrument panel, left of steering column. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  30 .
  28. Check for short to ground or short to battery voltage in Purple wire between IPC connector C1 terminal B8 and theft deterrent module connector terminal "D". If short was found, go to step  70 . If circuit is okay, go to next step.
  29. Replace theft deterrent module. After replacement, go to step  71 .
  30. If vehicle is equipped with power tilt/telescoping steering column, go to next step. If vehicle is not equipped with power tilt/telescoping steering column, go to step  33 .
  31. Disconnect steering column tilt/telescoping module connector. Module is located on left side of the instrument panel, left of steering column. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  33 .
  32. Replace steering column tilt/telescoping module. After replacement, go to step  71 .
  33. If vehicle is equipped with navigation display, go to step  37 . If vehicle is not equipped with navigation display, go to next step.
  34. Disconnect radio connector. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  37 .
  35. Check for short to ground or short to battery voltage in Purple wire between radio connector terminal E6 and theft deterrent module connector terminal "E". If short was found, go to step  70 . If circuit is okay, go to next step.
  36. Replace radio. After replacement, go to step  71 .
  37. Disconnect Instrument Panel Integration Module (IPM) connector. IPM is part of A/C-heater control panel. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  40 .
  38. Check for short to ground or short to battery voltage in Purple wire between IPM connector C1 terminal C7 and either theft deterrent module connector terminal "E" (with UY4) or radio connector terminal F6 (without UY4). See Fig 2 . If short was found, go to step  70 . If circuit is okay, go to next step.
  39. Replace IPM. See INSTRUMENT PANEL INTEGRATION MODULE (IPM)  under REMOVAL & INSTALLATION. After replacement, go to step  71 .
  40. Disconnect Left Front Door Module (LFDM) connector. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  42 .
  41. Replace LFDM. After replacement, go to step  71 .
  42. Disconnect Remote Keyless Entry Module (RKE) connector. Module is located under center of rear package tray shelf. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  44 .
  43. Replace RKE module. After replacement, go to step  71 .
  44. If vehicle is equipped with radio amplifier, go to step  47 . If vehicle is not equipped with radio amplifier, go to next step.
  45. Disconnect radio amplifier connector. Amplifier is located behind rear seat back on left side. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  56 .
  46. Check for short to ground or short to battery voltage in Purple wire between radio amplifier connector C1 terminal B11 (with U48) or connector C3 terminal No. 5 (with U49) and one of the following components:
    • RKE module connector terminals No. 3 and 4.
    • MSM connector C2 terminals D14 and D15.
    • LFDM connector C1 terminal No. 13.
    • PCM connector C1 terminal No. 58.

    If short was found, go to step  70 . If circuit is okay, go to step  55 .

  47. Disconnect radio connector. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  50 .
  48. Check for short to ground or short to battery voltage in Purple wire between radio connector C1 terminal E6 and RKE connector terminal No. 3. If short was found, go to step  70 . If circuit is okay, go to next step.
  49. Replace radio. After replacement, go to step  71 .
  50. Disconnect navigation data processor connector. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  53 .
  51. Check for short to ground or short to battery voltage in Purple wire between radio connector C1 terminal E6 and navigation data processor connector C1 terminal No. 2. If short was found, go to step  70 . If circuit is okay, go to next step.
  52. Replace navigation data processor. After replacement, go to step  71 .
  53. Disconnect radio amplifier connector. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  56 .
  54. Check for short to ground or short to battery voltage in Purple wire between radio amplifier connector C1 terminal B11 (with U48) or connector C3 terminal No. 5 (with U49) and navigation data processor connector C1 terminal No. 3. If short was found, go to step  70 . If circuit is okay, go to next step.
  55. Replace radio amplifier. After replacement, go to step  71 .
  56. If vehicle is equipped with real time dampening, go to next step. If vehicle is not equipped with real time dampening, go to step  60 .
  57. Disconnect Continuous Variable Road Sensing Suspension (CVRSS) module connector. Module is located behind rear seat back on right side. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  60 .
  58. Check for short to ground or short to battery voltage in Purple wire between radio amplifier and CVRSS connector C1 terminal D4. If short was found, go to step  70 . If circuit is okay, go to next step.
  59. Replace CVRSS module. After replacement, go to step  71 .
  60. Disconnect Rear Integration Module (RIM) connector. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  63 .
  61. Check for short to ground or short to battery voltage in Purple wire between RIM connector C2 terminal B3 and CVRSS connector C1 terminal D5 (with F45) or radio amplifier (without F45). See Fig 3 . If short was found, go to step  70 . If circuit is okay, go to next step.
  62. Replace RIM. See REAR INTEGRATION MODULE (RIM)  under REMOVAL & INSTALLATION. After repairs, go to step  71 .
  63. Disconnect Sensing and Diagnostic Module (SDM) connector. Module is located under passenger's seat. Attempt to communicate with DIM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  66 .
  64. Check for short to ground or short to battery voltage in Purple wire between SDM connector terminal No. 5 and RIM connector C2 terminal B4 or Cellular telephone module connector terminal No. 9. If short was found, go to step  70 . If circuit is okay, go to next step.
  65. Replace SDM. See appropriate AIR RESTRAINT SYSTEMS article. After replacement, go to step  71 .
  66. Reconnect IPM connector. Disconnect Dash Integration Module (DIM) connector. Attempt to communicate with IPM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step  69 .
  67. Check for short to ground or short to battery voltage in Purple wire between SDM connector terminal No. 17 and DIM connector C2 terminal A11. See Fig 1 . If short was found, go to step  70 . If circuit is okay, go to next step.
  68. Replace DIM. See DASH INTEGRATION MODULE (DIM)  under REMOVAL & INSTALLATION. After replacement, go to step  71 .
  69. Repair short to ground or short to battery voltage in Purple wire between DLC terminal No. 2 and IPC connector C1 terminal B8 or DIM connector C2 terminal A12. After repairs, go to step  71 .
  70. Repair short to ground or short to battery voltage in Purple wire. After repairs, go to next step.
  71. Reconnect all disconnected components. Use scan tool to clear DTCs. Perform DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK  .
Fig 1: Identifying Dash Integration Module (DIM) Connectors & Terminals
G99B05531Courtesy of GENERAL MOTORS CORP.
Fig 2: Identifying Instrument Panel Module (IPM) Connectors & Terminals
G99H05529Courtesy of GENERAL MOTORS CORP.
Fig 3: Identifying Rear Integration Module (RIM) Connectors & Terminals
G99D05532Courtesy of GENERAL MOTORS CORP.
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