B1025
DTC B1025, B1035, B1045, or B1055
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.
DTC Descriptor
DTC B1025
- Speaker Output Shorted
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. In an amplified audio system, these similar AC voltage measurements may be slightly higher on the output of the amplifier, and the typical AC voltage readings at the output of the radio are less than 1V AC.
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 the specified (+) or (-) speaker output signal circuit.
Action Taken When the DTC Sets
The radio disables audio output on the appropriate channel
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. Each of the four channels should produce clear and even sound.
Circuit/System Testing
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.
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