For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | 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 | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Amplifier B+ | -- | 2 | -- | --
Left Front Speaker Output (+)/Left Front Low Level Audio Signal (+) | B1025 02, * | 1 | B1025 01, * | --
Left Front Speaker Output (-)/Left Front Low Level Audio Signal (-) | B1025 02, * | 1 | B1025 01, * | --
Right Front Speaker Output (+)/Right Front Low Level Audio Signal (+) | B1035 02, * | 1 | B1035 01, * | --
Right Front Speaker Output (-)/Right Front Low Level Audio Signal (-) | B1035 02, * | 1 | B1035 01, * | --
Left Rear Speaker Output (+)/Left Rear Low Level Audio Signal (+) | B1045 02, * | 1 | B1045 01, * | --
Left Rear Speaker Output (-)/Left Rear Low Level Audio Signal (-) | B1045 02, * | 1 | B1045 01, * | --
Right Rear Speaker Output (+)/Right Rear Low Level Audio Signal (+) | B1055 02* | 1 | B1055 01, * | --
Right Rear Speaker Output (-)/Right Rear Low Level Audio Signal (-) | B1055 02* | 1 | B1055 01, * | --
Rear Subwoofer Speaker Output (+) | 1 | 1 | 1 | --
Rear Subwoofer Speaker Output (-) | 1 | 1 | 1 | --
Amplifier Ground | -- | 2 | -- | --
1. No or reduced sound from speaker 2. Amplifier inoperative/no sound from speakers * Noticeable audio distortion possible

### 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.

### Conditions for Running the DTC

• | The radio is 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 (+) 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.

### Reference Information

#### Schematic Reference

Entertainment/Communication Schematic Icons

#### Connector End View Reference

Entertainment/Communication Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Scan Tool Data List

### 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 C3 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 12

• | Left front low level audio signal (-) terminal 10

• | Right front low level audio signal (+) terminal 9

• | Right front low level audio signal (-) terminal 11

• | Left rear low level audio signal (+) terminal 3

• | Left rear low level audio signal (-) terminal 1

• | Right rear low level audio signal (+) terminal 4

• | Right rear low level audio signal (-) terminal 2

⇒ | 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.

⇒ | If greater than the specified range, test the appropriate signal circuit for a short to voltage. 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 after completing the diagnostic procedure.

• | Speaker Replacement Reference

• | Control Module References for audio amplifier and radio replacement, setup, and programming