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Home >> Cadillac >> 2007 >> DTS 4.6 9 >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Communication Devices >> Data Communication 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 all of the harness connectors of the CCSM.
  2. Test for less than 1 ohm of resistance between the module ground circuit and ground.
    • If greater than 1 ohm, repair the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the battery positive voltage circuit and ground.
    • If the test lamp does not illuminate, repair the circuit for a short to ground or an open/high resistance. If the circuit fuse is open, also test the positive voltage outputs of the module for a short to ground. If the circuits test normal, replace the CCSM.
  4. Verify that a test lamp illuminates between the ignition voltage circuits and ground.
    • If the test lamp does not illuminate, repair the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit fuse is open, also test the positive voltage outputs of the module for a short to ground. If the circuits test normal, replace the CCSM.
  5. Test for infinite resistance between the data link connector (DLC) keyword 2000 serial data circuit and ground.
    • If less than the specified value, test the serial data circuit for a short to ground.
  6. Test for less than 1 volt between the DLC keyword 2000 serial data circuit and ground.
    • If greater than the specified range, test the serial data circuit for a short to voltage.
  7. Test for less than 1 ohm of resistance in the keyword 2000 serial data circuit between the CCSM and the DLC.
    • 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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