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 | -- | --
Left Front Low Level Audio Signal/ Speaker Output | B1025 02, * | B1025 04, * | B1025 01, * | --
Right Front Low Level Audio Signal/ Speaker Output | B1035 02, * | B1035 04, * | B1035 01, * | --
Left Rear Low Level Audio Signal/ Speaker Output | B1045 02, * | B1045 04, * | B1045 01, * | --
Right Rear Low Level Audio Signal/ Speaker Output | B1055 02* | B1055 04* | B1055 01, * | --
Subwoofer Low Level Audio Signal/ Speaker Output | 2 | 2 | 2 | --
Center Low Level Audio Signal/ Speaker Output | 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.

### 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.

• | The amplifier control circuit has less than 1V when the mute function is OFF, and will have 4-6V DC when at full mute.

### 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, Mute OFF, 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 the appropriate Speaker Circuit Malfunction.

### Circuit/System Testing

Note: If equipped with surround sound, the surround sound should be turned OFF for proper voltage values when performing speaker testing.

#### Amplifier Circuit Malfunction -- UQA

1. Ignition OFF, disconnect the X1 harness connector at the T3 audio amplifier.
2. Ignition OFF, test for less than 10 Ω between the ground circuit terminal 4 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 8 and ground.

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

4. Ignition OFF, disconnect the X3 harness connector at the T3 audio amplifier.
5. Radio ON, test for B+ between the signal circuit terminal 13 and ground.

⇒ | If less than the specified value, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the A11 radio.

6. Radio ON, test for less than 1 V between the amplifier control circuit terminal 6 and ground.

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

7. If all circuits test normal, replace the T3 audio amplifier.

#### Amplifier Circuit Malfunction -- UQS

1. Ignition OFF, disconnect the X1 harness connector at the T3 audio amplifier.
2. Ignition OFF, test for less than 10 Ω between the ground circuit terminal 8 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 4 and ground.

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

4. Ignition OFF, disconnect the X3 harness connector at the T3 audio amplifier.
5. Radio ON, test for B+ between the signal circuit terminal 13 and ground.

⇒ | If less than the specified value, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the A11 radio.

6. Radio ON, test for 6-8 V between the amplifier control circuit terminal 6 and ground.

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

7. If all circuits test normal, replace the T3 audio amplifier.

#### Speaker Malfunction Radio Output Testing -- UQA

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.

#### Speaker Malfunction Radio Output Testing -- UQS

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

• | Center low level audio signal (+) - terminal 7 X3

• | Center low level audio signal (-) - terminal 15 X3

• | Subwoofer low level audio signal (+) - terminal 8 X3

• | Subwoofer low level audio signal (-) - terminal 16 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.

#### Speaker Malfunction Amplifier Output Testing RPO UQA

1. Ignition OFF, disconnect the X1 and X2 connectors at the T3 amplifier.
2. Radio ON, test for less than 1 volt between the appropriate signal circuit terminal listed below and ground:

• | Left front speaker output (+) - terminal 10 X2

• | Left front speaker output (-) - terminal 2 X2

• | Right front speaker output (+) - terminal 11 X2

• | Right front speaker output (-) - terminal 3 X2

• | Left rear speaker output (+) - terminal 12 X2

• | Left rear speaker output (-) - terminal 4 X2

• | Right rear speaker output (+) - terminal 13 X2

• | Right rear speaker output (-) - terminal 5 X2

• | Front center speaker output (+) - terminal 14 X2

• | Front center speaker output (-) - terminal 6 X2

• | Rear subwoofer speaker output (+) - terminal 6 X1

• | Rear subwoofer speaker output (-) - terminal 2 X1

• | Rear subwoofer speaker output (+) - terminal 7X1

• | Rear subwoofer speaker output (-) - terminal 3 X1

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

3. Radio ON, test for infinite resistance between the appropriate signal circuit terminal listed below and ground:

• | Left front speaker output (+) - terminal 10 X2

• | Left front speaker output (-) - terminal 2 X2

• | Right front speaker output (+) - terminal 11 X2

• | Right front speaker output (-) - terminal 3 X2

• | Left rear speaker output (+) - terminal 12 X2

• | Left rear speaker output (-) - terminal 4 X2

• | Right rear speaker output (+) - terminal 13 X2

• | Right rear speaker output (-) - terminal 5 X2

• | Front center speaker output (+) - terminal 14 X2

• | Front center speaker output (-) - terminal 6 X2

• | Rear subwoofer speaker output (+) - terminal 6 X1

• | Rear subwoofer speaker output (-) - terminal 2 X1

• | Rear subwoofer speaker output (+) - terminal 7X1

• | Rear subwoofer speaker output (-) - terminal 3 X1

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

4. If all circuits test normal, reconnect all harness connectors at the T3 amplifier.
5. Ignition ON, radio ON, disconnect the appropriate speaker.
6. Test for 4-8 V between the signal circuit terminals and ground.

⇒ | If less then the specified range, test the circuit for an open/high resistance. If the circuit tests normal, replace the T3 amplifier.

⇒ | If greater then the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the T3 amplifier.

7. If the circuit tests normal, replace the speaker.

#### Speaker Malfunction Amplifier Output Testing RPO Code UQS

1. Ignition OFF, disconnect the X1 and X2 connectors at the T3 amplifier.
2. Radio ON, test for less than 1 volt between the appropriate signal circuit terminal listed below and ground:

• | Left front speaker output (+) - terminal 10 X2

• | Left front speaker output (-) - terminal 2 X2

• | Right front speaker output (+) - terminal 11 X2

• | Right front speaker output (-) - terminal 3 X2

• | Left rear speaker output (+) - terminal 4 X2

• | Left rear speaker output (-) - terminal 12 X2

• | Right rear speaker output (+) - terminal 5 X2

• | Right rear speaker output (-) - terminal 13 X2

• | Front center speaker output (+) - terminal 14 X2

• | Front center speaker output (-) - terminal 6 X2

• | Rear subwoofer speaker output (+) - terminal 3 X1

• | Rear subwoofer speaker output (-) - terminal 7 X1

• | Rear subwoofer speaker output (+) - terminal 2 X1

• | Rear subwoofer speaker output (-) - terminal 6 X1

• | Left surround speaker output (+) - terminal 15 X2

• | Right surround speaker output (-) - terminal 7 X2

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

3. Radio ON, test for infinite resistance between the appropriate signal circuit terminal listed below and ground:

• | Left front speaker output (+) - terminal 10 X2

• | Left front speaker output (-) - terminal 2 X2

• | Right front speaker output (+) - terminal 11 X2

• | Right front speaker output (-) - terminal 3 X2

• | Left rear speaker output (+) - terminal 4 X2

• | Left rear speaker output (-) - terminal 12 X2

• | Right rear speaker output (+) - terminal 5 X2

• | Right rear speaker output (-) - terminal 13 X2

• | Front center speaker output (+) - terminal 14 X2

• | Front center speaker output (-) - terminal 6 X2

• | Rear subwoofer speaker output (+) - terminal 3 X1

• | Rear subwoofer speaker output (-) - terminal 7 X1

• | Rear subwoofer speaker output (+) - terminal 2 X1

• | Rear subwoofer speaker output (-) - terminal 6 X1

• | Left surround speaker output (+) - terminal 15 X2

• | Right surround speaker output (-) - terminal 7 X2

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

4. If all circuits test normal, reconnect all harness connectors at the T3 amplifier.
5. Ignition OFF, disconnect the appropriate speaker.
6. Radio ON, test for 4-8 V volts between the signal circuit terminals and ground.

⇒ | If less then the specified range test the circuit for an open/high resistance. If the circuit tests normal, replace the T3 amplifier.

⇒ | If greater then the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the T3 amplifier.

7. If the circuit tests normal, replace the speaker.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Speaker Replacement Reference

• | Control Module References for amplifier or radio replacement