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 provide an overview of each diagnostic category.

### DTC Descriptors

DTC B1025 01: Left Front Audio Output Circuit Short to Battery
DTC B1025 02: Left Front Audio Output Circuit Short to Ground
DTC B1025 04: Left Front Audio Output Circuit Open
DTC B1035 01: Front Audio Output Circuit Short to Battery
DTC B1035 02: Right Front Audio Output Circuit Short to Ground
DTC B1035 04: Right Front Audio Output Circuit Open
DTC B1045 01: Left Rear Audio Output Circuit Short to Battery
DTC B1045 02: Left Rear Audio Output Circuit Short to Ground
DTC B1045 04: Left Rear Audio Output Circuit Open
DTC B1055 01: Right Rear Audio Output Circuit Short to Battery
DTC B1055 02: Right Rear Audio Output Circuit Short to Ground
DTC B1055 04: Right Rear Audio Output Circuit Open

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Amplifier B+ | -- | 1 | -- | --
Left Front Low Level Audio Signal | B1025 02, * | B1025 04, * | B1025 01, * | --
Right Front Low Level Audio Signal | B1035 02, * | B1035 04, * | B1035 01, * | --
Left Rear Low Level Audio Signal | B1045 02, * | B1045 04, * | B1045 01, * | --
Right Rear Low Level Audio Signal | B1055 02* | B1055 04* | B1055 01, * | --
Subwoofer Low Level Audio Signal | 2 | 2 | 2 | --
Center Low Level Audio Signal | 3 | 3 | 3 | --
Amplifier Ground | -- | 1 | -- | --
1. Amplifier inoperative/no sound from subwoofers. 2. No or reduced sound from subwoofer. 3. No sound from center speaker. * 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. The amplifier can not set DTCs.

### Conditions for Running the DTC

• | The ignition is in the RUN or ACC position.

• | The system voltage is at least 9.5 volts and no more than 15.5 volts.

• | All the above conditions are present for greater than 10 seconds.

### Conditions for Setting the DTC

#### B1025 01, B1035 01, B1045 01, B1055 01

The radio detects a short to voltage on the audio (+) or audio (-) circuit.

#### B1025 02, B1035 02, B1045 02, B1055 02

The radio detects a short to ground on the audio (+) or audio (-) circuit.

#### B1025 04, B1035 04, B1045 04, B1055 04

The radio detects an open on the audio (+) or audio (-) circuit.

### Action Taken When the DTC Sets

The radio disables the audio output to the speaker signal circuit with the current fault.

### Conditions for Clearing the DTC

• | A current DTC clears when the conditions for setting the DTC are no longer present and the ignition has been cycled from OFF to ON.

• | A history DTC clears after 50 malfunction-free ignition cycles.

### Reference Information

#### Schematic Reference

Radio/Navigation System Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Radio/Audio System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

Radio ON, adjust the fade and balance controls on the radio to test all channels individually. Each channel 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 4-8 V 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 A11 radio.

⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the A11 radio.

3. Test for 4-8 V 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 A11 radio.

⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the A11 radio.

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

#### With Amplifier

1. Ignition OFF, disconnect the X3 harness connector at the T3 amplifier.
2. Radio ON, test for 4-8 V between the appropriate signal circuit terminal listed below and ground.

• | Left front low level audio signal (+) - terminal 9 X3

• | Left front low level audio signal (-) - terminal 1 X3

• | Right front low level audio signal (+) - terminal 10 X3

• | Right front low level audio signal (-) - terminal 2 X3

• | Left rear low level audio signal (+) - terminal 11 X3

• | Left rear low level audio signal (-) - terminal 3 X3

• | Right rear low level audio signal (+) - terminal 12 X3

• | Right rear low level audio signal (-) - terminal 4 X3

⇒ | 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 A11 radio.

⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the A11 radio.

3. If all circuits test normal, replace the T3 amplifier.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Speaker Replacement Reference

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