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Home >> Buick >> 2011 >> Lucerne CX >> Repair and Diagnosis >> Engine Performance >> System >> Data Communications System >> Diagnostic Information and Procedures >> Scan Tool Does Not Communicate with Keyword Data Line >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the harness connectors X1, X2, and X3 of the CCSM.
  2. Test for less than 1Ω between the module ground circuit terminal M X1 and ground.
    • If greater than the specific range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the battery positive voltage circuit terminal E X1 and ground.
    • If the test lamp does not illuminate, test the battery positive voltage circuit for a short to ground or an open/high resistance. If the circuit fuse is open, test the positive voltage outputs of the module for a short to ground. If all circuits test normal, replace the CCSM.
  4. Ignition ON, verify that a test lamp illuminates between ignition voltage circuit terminal 1 X2 and ground.
    • If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit fuse is open, test the positive voltage outputs of the module for a short to ground. If all circuits test normal, replace the CCSM.
  5. Test for infinite resistance between the data link connector (DLC) keyword 2000 serial data circuit terminal 7 and ground.
    • If less than the specified value, test the serial data circuit for a short to ground.
  6. Test for less than 1V between the DLC keyword 2000 serial data circuit terminal 7 and ground.
    • If greater than the specified range, test the serial data circuit for a short to voltage.
  7. Test for less than 1Ω in the keyword 2000 serial data circuit between the CCSM terminal 9 X3 and the DLC terminal 7.
    • If greater than the specified range, test the serial data circuit for open/high resistance.
  8. If all circuits test normal, replace CCSM.
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