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Home >> Cadillac >> 2017 >> ATS Base, 4D Sedan, RWD, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 174 (Cellular System, Entertainment System, And Navigation System - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC B1025-B1215: Audio Output(UQH) >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2016 Cadillac CT6. However, it is still accessible from the selected car via links, so may be relevant.

Speaker Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate P19 speaker. Ignition On/Vehicle in Service Mode. Infotainment system ON, mute OFF.
  2. Test for 5-7 V between the appropriate signal circuit terminals listed below and ground.
    • Door, and Left I/P, Right I/P, Rear shelf, Rear center speakers audio (-) circuit terminal 1
    • Door, and Left I/P, Right I/P, Rear shelf, Rear center speakers audio (+) circuit terminal 2
    • A-Pillar speakers audio (-) circuit terminal 3
    • A-Pillar speakers audio (+) circuit terminal 4
    • Center I/P speakers audio (-) circuit terminal 6
    • Center I/P speakers audio (+) circuit terminal 1
    • Headrest speakers audio (-) circuit terminal A
    • Headrest speakers audio (+) circuit terminal B
    • If less than 5 V 
    1. Ignition OFF, disconnect the appropriate harness connector(s) at the T3 audio amplifier.
    2. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the T3 audio amplifier.
    • If greater than 7 V 
    1. Ignition OFF, disconnect the appropriate harness connector(s) at the T3 audio amplifier.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the T3 audio amplifier.
    • If between 5-7 V 
  3. Test or replace the P19 speaker.

Subwoofer Circuit Malfunction

  1. Ignition OFF, disconnect the X1 harness connector at the appropriate secondary audio amplifier.
  2. Test for less than 10 Ω between the appropriate ground circuit terminal listed below and ground.
    • Left and Right Front Subwoofer circuit terminal 6
    • Rear Subwoofer circuit terminal 14
    • If 10 Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • If less than 10 Ω 
  3. Ignition On/Vehicle in Service Mode. Verify a test lamp illuminates between the appropriate B+ circuit terminal listed below and ground.
    • Left and Right Front Amplifier circuit terminal 3
    • Rear Amplifier circuit terminal 7
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF, remove the test lamp.
    2. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF, remove the test lamp.
    2. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the secondary amplifier
    • If the test lamp illuminates 
  4. Ignition OFF, disconnect the X1 harness connector at the appropriate secondary amplifier, Ignition On/Vehicle in Service Mode.
  5. Radio ON, Test for 2.5-3.5 V between the appropriate control circuit listed below and ground.
    • Left and Right Front Amplifier circuit terminal 2
    • Rear Amplifier circuit terminal 5
    • If less than 2.5 V 
    1. Ignition OFF, disconnect the appropriate harness connector at the T3 Audio Amplifier.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the T3 Audio Amplifier.
    • If greater than 3.5 V 
    1. Ignition OFF, disconnect the appropriate harness connector at the T3 Audio Amplifier.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the T3 Audio Amplifier.
    • If between 2.5-3.5 V 
  6. Radio ON, mute OFF.
  7. Test for 3-5 V between the appropriate signal circuit terminals listed below and ground:
    • Left and Right front subwoofer control (+) circuit terminal 4
    • Left and Right front subwoofer control (-) circuit terminal 5
    • Rear Subwoofer control (+) circuit terminal 3
    • Rear Subwoofer control (-) circuit terminal 2
    • If less than 3 V 
    1. Ignition OFF, disconnect the X4 harness connector at the T3 Amplifier.
    2. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the T3 audio amplifier.
    • If greater than 5 V 
    1. Ignition OFF, disconnect the X4 harness connector at the T3 amplifier, Ignition On/Vehicle in Service Mode.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the T3 audio amplifier.
    • If between 3-5 V 
  8. Ignition OFF, connect all harness connectors.
  9. Disconnect the harness connector at the appropriate P19 Speaker. Ignition On/Vehicle in Service Mode. Radio ON.
  10. Test for 5-7 V between the appropriate signal circuit terminals listed below and ground:
    • Left and Right front subwoofer control (+) circuit terminal 2
    • Left and Right front subwoofer control (-) circuit terminal 1
    • Rear Subwoofer control (+) circuit terminal B
    • Rear Subwoofer control (-) circuit terminal A
    • If less than 5 V 
    1. Ignition OFF, disconnect the X1 harness connector at the Secondary Amplifier.
    2. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the secondary amplifier.
    • If greater than 7 V 
    1. Ignition OFF, disconnect the X1 harness connector at the Secondary amplifier, Ignition On/Vehicle in Service Mode.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the Secondary amplifier.
    • If between 5-7 V 
  11. Test or replace the P19 Speaker.
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