GM Service Manual Online
For 1990-2009 cars only

Circuit Description

When the radio is powered up, the radio supplies low level audio signals to the speakers. If the vehicle is equipped with an audio amplifier, the amplifier will boost the signal sent to the speakers.

DTC Descriptor

This diagnostic procedure supports the following DTCs:

    • DTC B1025 Audio Output 1 Circuit
    • DTC B1035 Audio Output 2 Circuit
    • DTC B1045 Audio Output 3 Circuit
    • DTC B1055 Audio Output 4 Circuit

Conditions for Running the DTC

The test is performed when the radio switches from OFF to ON. The radio will continue to test for the fault once every 0.5 seconds.

Conditions for Setting the DTC

The radio sets a current status for this DTC when a short to ground or voltage is detected on any of the speaker channels for 1.5 seconds.

Action Taken When the DTC Sets

No sound is present from one or more of the speakers.

Conditions for Clearing the DTC

The fault condition is not present for 5 seconds.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step verifies that the DTC is still present.

  2. This step isolates the fault condition.

Step

Action

Yes

No

Schematic Reference: Radio/Navigation System Schematics

Connector End Views Reference: Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With the scan tool, monitor the DTC information for DTC B1025.

Does the scan tool indicate that DTC B1025 is current?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

3

Test the speaker outputs for short to ground or voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 6

Go to Step 4

4

Inspect for poor connections at the harness connector of the radio. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 6

Go to Step 5

5

Replace the radio. Refer to Radio Replacement .

Did you complete the replacement?

Go to Step 6

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6

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2