B1035

DTC B1025, B1035, B1045, or B1055

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.

DTC Descriptor
DTC B1025
- Audio Output Circuit Shorted to Battery or Ground

Diagnostic Fault Information





Circuit/System Description

Each of the audio output channel circuits (+) and (-) at the radio and amplifier have a varying AC voltage. Each of the audio output channel circuits at the audio amplifier also have a DC bias voltage that is approximately one half of battery voltage. The audio being played on the system is produced by a varying AC voltage that is centered around the DC bias voltage on the same circuit. The AC voltage is what causes the speaker cone to move and produce sound. Both the DC bias voltage and the AC voltage signals are needed for the speakers to properly produce sound. The frequency (Hz) of the AC voltage signal is directly related to the frequency of the input (audio source playing) to the audio system. The AC voltage will vary depending on what type of audio is being listened to, as well as the volume setting of the system.

Conditions for Running the DTC

* Radio ON.
* Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

The DTC will set when the radio detects a short to voltage or short to ground in any of the low level audio signal circuits (+) or (-).

Action Taken When the DTC Sets

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

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Reference Information
Schematic Reference

Radio/Navigation System Schematics (Radio/Navigation System Schematics)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

Radio/Audio System Description and Operation (Radio/Audio System)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the X3 harness connector at the audio amplifier.
2. Ignition ON, radio ON, mute OFF, test for a varying AC mV reading between the following signal circuit terminals listed below and ground.

* Left front low level audio signal (+) terminal 15
* Left front low level audio signal (-) terminal 7
* Right front low level audio signal (+) terminal 14
* Right front low level audio signal (-) terminal 6
* Left rear low level audio signal (+) terminal 13
* Left rear low level audio signal (-) terminal 5
* Right rear low level audio signal (+) terminal 12
* Right rear low level audio signal (-) terminal 4

• If not the specified value, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the radio.

3. If all circuits test normal, replace the audio amplifier.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Speaker Replacement Reference (Speaker Replacement Reference)
* Control Module References (Programming and Relearning)for audio amplifier or radio replacement, setup, and programming