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DTC U1144: Loss Of Communications With PHN: Testing

  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, perform data link communications diagnostic system check. See DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK  under SYSTEM TESTS.
  2. Using scan tool, attempt to establish communications with cellular phone module. If scan tool communicates with cellular phone module, go to next step. If scan tool does not communicate with cellular phone module, diagnose cellular phone system.
  3. Check and repair class 2 serial data line circuit No. 1807 (Purple wire) for intermittent conditions. See appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS. After repairs, go to next step.
  4. Turn ignition switch to OFF position. Reconnect components and connectors. Turn ignition switch to ON position. Using scan tool, clear DTCs. Perform DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK  under SYSTEM TESTS.
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