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Home >> Cadillac >> 2007 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 1038 (Cellular System, Entertainment System, And Navigation System) >> Diagnostic Information and Procedures >> DTC B1025, B1035, B1045, or B1055 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT: The DTC can be set by either the radio or the amplifier. If the DTC was set by the radio, diagnose suspect audio input circuits to the speakers or the amplifier (if equipped). Diagnose audio input signals to the speakers from the amplifier if the DTC was set by the amplifier.

Without Amplifier

  1. Ignition OFF, disconnect the harness connector at the appropriate speaker.
  2. Radio ON, test for 5.0-7.5 volts between the signal circuit terminal A and ground.
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
  3. Test for 5.0-7.5 volts between the signal circuit terminal B and ground.
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
  4. If all circuits test normal, test or replace the speaker.

With Amplifier

  1. Ignition OFF, disconnect the X1(except UQS) or X4(UQS)and X3 harness connectors at the amplifier.
  2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    • Left front door or tweeter - Connector X2, terminal 3
    • Right front door or tweeter - Connector X2, terminal 1
    • Left rear speaker - Connector X2, terminal 7
    • Left rear subwoofer - Connector X3, terminal 3
    • Right rear speaker - Connector X2, terminal 5
    • Right rear subwoofer - Connector X3, terminal 2
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
  3. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    • Left front door or tweeter - Connector X2, terminal 4
    • Right front door or tweeter - Connector X2, terminal 2
    • Left rear speaker - Connector X2, terminal 8
    • Left rear subwoofer - Connector X3, terminal 7
    • Right rear speaker - Connector X2, terminal 6
    • Right rear subwoofer - Connector X3, terminal 6
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
  4. If all circuits test normal, replace the amplifier.
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