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.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Left Front Speaker Output (+) | B1025* | 1 | B1025* | --
Left Front Speaker Output (-) | B1025* | 1 | B1025* | --
Right Front Speaker Output (+) | B1035* | 1 | B1035* | --
Right Front Speaker Output (-) | B1035* | 1 | B1035* | --
Left Rear Speaker Output (+) | B1045* | 1 | B1045* | --
Left Rear Speaker Output (-) | B1045* | 1 | B1045* | --
Right Rear Speaker Output (+) | B1055* | 1 | B1055* | --
Right Rear Speaker Output (-) | B1055* | 1 | B1055* | --
1. No or reduced sound from speaker * Noticeable audio distortion possible

### 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.

### 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, verify clear audio is heard from each audio speaker.

⇒ | If audio is inoperative from all speakers, replace the radio.

⇒ | If audio is inoperative from one or more, but not all, speakers or the audio emitted from the speakers is not clear, refer to Circuit/System Testing.

### Circuit/System Testing

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 terminals listed below and and ground.

• | Speaker terminal A

• | Speaker terminal B

• | Tweeter terminal 1

• | Tweeter terminal 2

⇒ | 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 speaker.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Speaker Replacement Reference

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