B1055

DTC B1025, B1035, B1045, or B1055

Diagnostic Instructions

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

DTC Descriptors

DTC B1025 01
- Audio Output 1 Left Front Circuit Short to Battery

DTC B1025 02
- Audio Output 1 Left Front Circuit Short to Ground

DTC B1035 01
- Audio Output 2 Right Front Circuit Short to Battery

DTC B1035 02
- Audio Output 2 Right Front Circuit Short to Ground

DTC B1045 01
- Audio Output 3 Left Rear Circuit Short to Battery

DTC B1045 02
- Audio Output 3 Left Rear Circuit Short to Ground

DTC B1055 01
- Audio Output 4 Right Rear Circuit Short to Battery

DTC B1055 02
- Audio Output 4 Right Rear Circuit Short to Ground

Diagnostic Fault Information






Circuit/System Description

Each of the audio output channel circuits (+) and (-), at the radio and audio amplifier 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

* 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, short to ground, or an open/high resistance in any of the low level audio signal circuits (+) and (-).

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.

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, replace the speaker.

With Amplifier
1. Ignition OFF, disconnect the X3 harness connector at the audio amplifier.
2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.

* Left front low level audio signal (+) terminal 1
* Left front low level audio signal (-) terminal 9
* Right front low level audio signal (+) terminal 2
* Right front low level audio signal (-) terminal 10

• If greater than the specified range, test the appropriate signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
• If less than the specified range, test the appropriate signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.

3. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.

* Left rear low level audio signal (+) terminal 3
* Left rear low level audio signal (-) terminal 11
* Right rear low level audio signal (+) terminal 4
* Right rear low level audio signal (-) terminal 12

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

Repair Instructions

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

* Speaker Replacement Reference