B1025, B1035, B1045, or B1055 (Non-Navigation Radio)

DTC B1025, B1035, B1045, or B1055 (Non-Navigation Radio)

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 Descriptors
DTC B1025
- Speaker Output Shorted to Ground or Voltage

Diagnostic Fault Information





Circuit/System Description

Each of the audio output channel circuits (+) and (-), at the radio and at the amplifier (if equipped) have a DC bias voltage that is one half of the battery voltage. When using a DMM, each of the audio output channel circuits will measure approximately 6.5V DC. 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. This voltage will vary depending on what type of audio is being listened to, talk or music, and type of music, as well as the volume setting of the system. Low volume and talk settings will measure around 1V AC and less, where constant music may measure 3V AC and slightly higher.

Conditions for Running the DTC

The radio is ON.

Conditions for Setting the DTC

A short to voltage or a short to ground is detected on a speaker output signal circuit.

Action Taken When the DTC Sets

The radio disables its outputs on one or more channels, producing no sound.

Conditions for Clearing the DTC

* A current DTC will clear when the conditions for setting are no longer seen.
* A history DTC will clear after 100 malfunction-free ignition cycles.

Reference Information
Schematic Reference

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

Component Connector End Views (Connector Views)
Description and Operation

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

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

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

Circuit/System Verification

Radio ON, adjust the fade and balance controls on the radio to test all four channels individually: All speakers should function properly.

Circuit/System Testing

Without Amplifier
1. Ignition OFF, disconnect the harness connector at the appropriate speaker.
2. Radio ON, test for 5.0-7.5V between the signal circuit terminal A and ground.

• 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.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.

3. Test for 5.0-7.5V between the signal circuit terminal B and ground.

• 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.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.

4. If all circuits test normal, replace the speaker.

With Amplifier
1. Ignition OFF, disconnect the X1 connector at the amplifier.
2. Radio ON, test for 5.0-7.5V between the appropriate signal circuit terminal listed below and ground.

* Left front low audio signal (+) - terminal 1
* Left front low audio signal (-) - terminal 2
* Right front low audio signal (+) - terminal 10
* Right front low audio signal (-) - terminal 9
* Left rear low audio signal (+) - terminal 4
* Left rear low audio signal (-) - terminal 3
* Right rear low audio signal (+) - terminal 11
* Right rear low audio signal (-) - terminal 12

• 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.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.

3. If all circuits test normal, replace the 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 radio or amplifier replacement, setup, and programming