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Home >> Buick >> 1999 >> Century Custom >> Repair and Diagnosis >> Body & Frame >> Body, Cab Control Systems >> Body Control Modules >> System Tests >> Data Link Connector (DLC) Diagnostic System Check >> Testing
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Data Link Connector (DLC) Diagnostic System Check: Testing

  1. Turn ignition off. Connect scan tool. Turn on scan tool. If scan tool turns on, go to next step. If scan tool does not turn on, diagnose and repair problem in DLC power or ground circuit.
  2. Turn ignition on. Using scan tool, attempt to establish communication with Powertrain Control Module (PCM). If communication can be established with PCM, go to next step. If communication cannot be established with PCM, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DATA LINE  .
  3. Attempt to establish communication with Electronic Brake Traction Control Module (EBTCM). If communication can be established with EBTCM, go to next step. If communication cannot be established with EBTCM, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DATA LINE  .
  4. Attempt to establish communication with Instrument Panel Cluster (IPC). If communication can be established with IPC, go to next step. If communication cannot be established with IPC, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DATA LINE  .
  5. If vehicle is not equipped with automatic climate control, go to next step. If vehicle is equipped with automatic climate control, attempt to establish communication with A/C-heater control. If communication can be established with A/C-heater control, go to next step. If communication cannot be established with A/C-heater control, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DATA LINE  .
  6. Attempt to establish communication with Body Control Module (BCM). If communication can be established with BCM, go to next step. If communication cannot be established with BCM, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DATA LINE  .
  7. Attempt to establish communication with Sensing and Diagnostic Module (SDM). If communication can be established with SDM, go to next step. If communication cannot be established with SDM, diagnose and repair problem between DLC and SDM. See appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS. See appropriate AIR BAG RESTRAINT SYSTEMS article.
  8. Attempt to establish communication with CD player (if equipped) and radio. If communication can be established with CD player and radio, system is operating properly. If communication cannot be established with CD player or radio, diagnose and repair problem between DLC and radio (E & C serial data line). See appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS.
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