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Home >> Cadillac >> 2007 >> STS Base, 3.6 7, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 112 (Cellular System, Entertainment System, And Navigation System) >> Diagnostic Information and Procedures >> No (or Noisy) OnStar Audio >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2009 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the X2 harness connector at the CIM.
  2. Test for less than 5 Ω between terminal 2 and ground.
    • If greater than the specified range, test the circuit for an open or high resistance. If the circuit tests normal, replace the audio amplifier.
  3. Reconnect the CIM X2 harness connector. Disconnect the X1 harness connector at the audio amplifier.
  4. Ignition ON, test for a momentary AC voltage between the appropriate signal circuit terminals listed below and ground when the OnStar® Call Center button is pressed.
    • terminal 3 (UX8)
    • terminal 7 (UY5)
    • If AC voltage was not present, test the circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the CIM.
  5. If all circuits test normal, replace the audio amplifier.
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