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Scan Tool Does Not Communicate With Keyword 82/Keyword 2000 Data Line

NOTE: To identify wire colors and modules on serial data links, see appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS.
  1. Ensure battery condition, cold cranking amperage and reserve capacity meet specifications. Replace as necessary. Install scan tool to Data Link Connector (DLC). If scan tool powers up, go to next step. If scan tool does not power up, go to SCAN TOOL DOES NOT POWER UP  .
  2. Turn ignition on, engine off. Using Figure as a reference, try to establish scan tool communication with each module on each data line in the following order:
    • Modules at terminal No. 7 of DLC connector: Transmission Control Module (TCM), Driver Memory Seat Module (DMSM), Instrument Panel Cluster (IPC) and Engine Control Module (ECM).
    • Modules at terminal No. 3 of DLC connector: Theft Deterrent Module and Sun Roof Actuator.
    • Modules at terminal No. 12 of DLC connector: Supplemental Inflatable Restraint (SIR) Module, Power Steering Control Module, Heater-A/C Control and Electronic Brake/Traction Control Module (EBTCM).
    If communication with modules on designated DLC terminal is established, go to next step. If communication with any module on designated DLC terminal is not established, go to step  4 .
  3. Locate and repair open in data circuit (Brown/White wire) between module not communicating and designated DLC terminal. See step  2 for DLC terminal assignment. If fault was located and repaired, perform diagnostic system check for system affected. If fault was not located and repaired, go to step  5 .
  4. Turn ignition off. Disconnect scan tool from DLC. Inspect for poor connections and bad terminal contact between DLC terminal (Brown/White wire) on which non-communicating module is connected and DLC terminals No. 4 and No. 5 (Black wires). See Figure . If fault was located and repaired, perform diagnostic system check for system affected. If fault was not located and repaired, go to step  6 .
  5. Test following circuits to module that is not communicating:
    • Battery positive voltage circuit for an open or short to ground.
    • Ignition positive voltage circuit for an open or short to ground.
    • Ground circuit for an open.
    • ECM power relay operation. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
    If fault was located and repaired, perform diagnostic system check for system affected. If fault was not located and repaired, go to step  7 .
  6. Test ground circuits (Black wires) at DLC terminals No. 4 and No. 5 for an open. See WIRING DIAGRAMS  . If fault was located and repaired, perform diagnostic system check for system affected. If fault was not located and repaired, go to step  8 .
  7. Inspect for poor connections and bad terminal contact at serial data harness connector of non-communicating module. If fault was located and repaired, perform diagnostic system check for system affected. If fault was not located and repaired, go to step  9 .
  8. Disconnect each module on serial data circuit to which non-communicating module is assigned. See step  2 for DLC terminal assignment. Test serial data circuit (Brown/White wire) between module not communicating and designated DLC terminal for short to ground (ignition off) or short to voltage (ignition on). If fault was located and repaired, perform diagnostic system check for system affected. If fault was not located and repaired, go to step  10 .
  9. Replace module not communicating. See REMOVAL & INSTALLATION  . After replacement, perform diagnostic system check for system affected.
  10. Reconnect module that was not communicating and all other disconnected in-line harness connectors. Turn ignition off and connect scan tool to DLC. Turn ignition on. Attempt to communicate with module that was not communicating. If scan tool communicates with module, go to next step. If scan tool does not communicate with module, go to step  14 .
  11. Continue connecting disconnected modules and attempting to communicate after each connection until communication cannot be established, or all modules are reconnected. If fault is located, go to next step. If fault is not located, go to PRELIMINARY INSPECTION  under TROUBLE SHOOTING.
  12. Replace most recently reconnected module. See REMOVAL & INSTALLATION  . After replacement, go to next step.
  13. Reconnect all disconnected modules and all other disconnected harness connectors. Turn ignition off and connect scan tool to DLC. Turn ignition on. Attempt to communicate with all modules on each serial data circuit. See step 2)  for DLC terminal assignment. If scan tool communicates with all modules, repairs are complete. System is okay.
  14. Inspect for poor connections and or terminal contact at serial data circuit (Brown/White wire) connector of most recently reconnected module. If fault is located, go to step  11 . If fault is not located, go to step  9 .
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