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Home >> Cadillac >> 2007 >> CTS Base, 2.8 T, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 747 (Cellular System, Entertainment System, And Navigation System) >> Diagnostic Information and Procedures >> OnStar Microphone Malfunction >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2013 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.

Microphone Malfunction

  1. Ignition OFF, disconnect the harness connector at the cellular phone microphone.
  2. Ignition ON, test for 9.5-10.5 V between the microphone high signal circuit terminal B and ground.
    • If less than the specified range, test the circuit for a short to ground, shorted together, or an open/high resistance. If the circuit tests normal, replace the vehicle communication interface control module.
    • If greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the vehicle communication interface control module.
  3. Test for 9.5-10.5 V between the microphone high signal circuit terminal B and the microphone low signal circuit terminal A.
    • If less than the specified range, test the low signal circuit for a short to ground, shorted together, or an open/high resistance. If the circuit tests normal, replace the vehicle communication interface control module.
    • If greater than the specified range, test the low signal circuit for a short to voltage. If the circuit tests normal, replace the vehicle communication interface control module.
  4. If all circuit test normal, replace the cellular phone microphone.

Cellular Telephone Voice Malfunction

  1. Ignition OFF, disconnect the appropriate harness connector at the radio.
    • X4 harness connector, (with UYS)
    • X1 harness connector, (without UYS)
  2. Disconnect the X3 harness connector at the vehicle communication interface control module.
  3. Ignition ON, test for less than 1 V between the vehicle communication interface control module voice recognition audio signal circuit terminal 2 X3 and ground.
    • If not the specified value, test the voice recognition audio signal circuit for a short to voltage.
  4. Test for less than 1 V between the vehicle communication interface control module voice recognition audio low reference circuit terminal 4 X3 and ground.
    • If not the specified value, test the voice recognition audio low reference circuit for a short to voltage.
  5. Ignition OFF, test for infinite resistance between the vehicle communication interface control module voice recognition audio signal circuit terminal 2 X3 and ground.
    • If not the specified value, test the voice recognition audio signal circuit for a short to ground.
  6. Test for infinite resistance between the vehicle communication interface control module voice recognition audio low reference circuit terminal 4 X3 and ground.
    • If not the specified value, test the voice recognition audio low reference circuit for a short to ground.
  7. Test for less than 2 Ω between the vehicle communication interface control module voice recognition audio signal circuit terminal 2 X3 and the appropriate radio terminal.
    • Voice Recognition Audio Signal Terminal 6 X4, (with UYS)
    • Voice Recognition Audio Signal Terminal 4 X1, (without UYS)
    • If not the specified value, test the voice recognition audio signal circuit for a open/high resistance.
  8. Test for less than 2 Ω between the vehicle communication interface control module voice recognition audio low reference circuit terminal 4 X3 and the appropriate radio terminal.
    • Voice Recognition Audio Low Signal Terminal 16 X4, (with UYS)
    • Voice Recognition Audio Low Signal Terminal 5 X1, (without UYS)
    • If not the specified value, test the voice recognition audio low reference circuit for a open/high resistance.
  9. If all circuits test normal, replace the vehicle communication interface control module.
  10. If all circuits test normal, replace the radio.
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