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
--- | --- | --- | --- | ---
Amplifier B+ | -- | 1 | -- | --
Radio ON/Amp Turn ON Signal | 1 | 1 | -- | --
Left Front Speaker Output (+)/Left Front Low Level Audio Signal (+) | B1025 02, * | 2 | B1025 01, * | --
Left Front Speaker Output (-)/Left Front Low Level Audio Signal (-) | B1025 02, * | 2 | B1025 01, * | --
Right Front Speaker Output (+)/Right Front Low Level Audio Signal (+) | B1035 02, * | 2 | B1035 01, * | --
Right Front Speaker Output (-)/Right Front Low Level Audio Signal (-) | B1035 02, * | 2 | B1035 01, * | --
Left Rear Speaker Output (+)/Left Rear Low Level Audio Signal (+) | B1045 02, * | 2 | B1045 01, * | --
Left Rear Speaker Output (-)/Left Rear Low Level Audio Signal (-) | B1045 02, * | 2 | B1045 01, * | --
Right Rear Speaker Output (+)/Right Rear Low Level Audio Signal (+) | B1055 02* | 2 | B1055 01, * | --
Right Rear Speaker Output (-)/Right Rear Low Level Audio Signal (-) | B1055 02* | 2 | B1055 01, * | --
Amplifier Ground | -- | 1 | -- | --
1. Amplifier inoperative/no sound from speakers 2. 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 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.

### Diagnostic Aids

• | Improper speaker mounting or loose trim may cause an audible buzz or distortion. Inspect the appropriate speaker and the surrounding interior trim for proper and secure mounting. If the speaker or surrounding interior trim is found to be loose or improperly secured, correctly secure the item.

• | When equipped with an amplifier, it is possible for some individual circuit faults to affect more than one speakers operation. Perform diagnostic tests in the sequence listed to avoid misdiagnosis.

### Reference Information

#### Schematic Reference

Radio/Navigation System Schematics

#### Connector End View Reference

Entertainment/Communication 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

### Circuit/System Verification

#### Without Amplifier

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 Speaker Circuit Malfunction - without Amplifier.

#### With Amplifier

Radio ON, verify clear audio is heard from each audio speaker.

⇒ | If audio is inoperative from all speakers, refer to Amplifier Circuit Malfunction.

⇒ | If audio is inoperative from one or more, but not all, speakers or the audio emitted from the speakers is not clear, refer to Speaker Circuit Malfunction - with Amplifier.

### Circuit/System Testing

#### Speaker Circuit Malfunction - without Amplifier

1. Disconnect the harness connector at the appropriate speaker.
2. Radio ON, test for 5.0-7.5V 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 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. Test for 5.0-7.5V 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 radio.

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

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

#### Amplifier Circuit Malfunction

1. Ignition OFF, disconnect the X1 harness connector at the audio amplifier.
2. Ignition OFF, test for less than 10Ω between the ground circuit terminal 2 and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, test for B+ between the B+ circuit terminal 1 and ground.

⇒ | If less then the specified value, test the B+ circuit for a short to ground or an open/high resistance.

4. Disconnect the X3 harness connector at the audio amplifier.
5. Radio ON, test for B+ between the signal circuit terminal 6 and ground.

⇒ | If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.

6. Test for 0.5-1.0V between the amplifier mute signal circuit terminal 16 and ground.

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

7. If all circuits test normal, replace the audio amplifier.

#### Speaker Circuit Malfunction - with Amplifier

1. Ignition OFF, disconnect the X3 harness connector at the audio amplifier.
2. Radio ON, test for 5.0-7.5V 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 2

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

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

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

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

• | Right rear low level audio signal (+) terminal 11

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

⇒ | 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. Ignition OFF, connect the X3 harness connector at the audio amplifier.
4. Disconnect the X2 and X1 harness connectors at the audio amplifier.
5. Ignition ON, test for less than 1V between each of the signal circuit terminals listed below and ground.

• | Left Front Speaker Output (+) terminal 15 X2

• | Left Front Speaker Output (-) terminal 16 X2

• | Right Front Speaker Output (+) terminal 13 X2

• | Right Front Speaker Output (-) terminal 14 X2

• | Left tweeter Speaker Output (+) terminal 2 X2

• | Left tweeter Speaker Output (-) terminal 1 X2

• | Right tweeter Speaker Output (+) terminal 4 X2

• | Right tweeter Speaker Output (-) terminal 3 X2

• | Left Rear Speaker Output (+) terminal 6 X2

• | Left Rear Speaker Output (-) terminal 5 X2

• | Right Rear Speaker Output (+) terminal 8 X2

• | Right Rear Speaker Output (-) terminal 7 X2

• | Left subwoofer output (+) terminal 3 X1

• | Left subwoofer output (-) terminal 4 X1

• | Right subwoofer output (+) terminal 8 X1

• | Right subwoofer output (-) terminal 7 X1

⇒ | If greater than the specified range, test both signal circuits of the affected speaker for a short to voltage.

6. Ignition OFF, test for infinite resistance between each of the signal circuit terminals listed below and ground.

• | Left Front Speaker Output (+) terminal 15 X2

• | Left Front Speaker Output (-) terminal 16 X2

• | Right Front Speaker Output (+) terminal 13 X2

• | Right Front Speaker Output (-) terminal 14 X2

• | Left tweeter Speaker Output (+) terminal 2 X2

• | Left tweeter Speaker Output (-) terminal 1 X2

• | Right tweeter Speaker Output (+) terminal 4 X2

• | Right tweeter Speaker Output (-) terminal 3 X2

• | Left Rear Speaker Output (+) terminal 6 X2

• | Left Rear Speaker Output (-) terminal 5 X2

• | Right Rear Speaker Output (+) terminal 8 X2

• | Right Rear Speaker Output (-) terminal 7 X2

• | Left subwoofer output (+) terminal 3 X1

• | Left subwoofer output (-) terminal 4 X1

• | Right subwoofer output (+) terminal 8 X1

• | Right subwoofer output (-) terminal 7 X1

⇒ | If less than the specified value, test both signal circuits of the affected speaker for a short to ground.

7. Ignition OFF, reconnect all harness connectors at the amplifier. Disconnect the harness connector at the appropriate speaker.
8. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminals listed below and ground.

• | Front door speakers - terminal A and B

• | Front tweeters - terminal A and B

• | Rear speakers - terminal A and B

• | Rear subwoofers - terminals A, B, C and D

⇒ | If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the amplifier.

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

9. 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 Audio Amplifier and Radio replacement, setup, and programming