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 |
|---|---|---|---|---|
Audio Amplifier B+ | 1, 2 | 1, 2 | -- | -- |
CD Changer B+ | 1, 3 | 1, 3 | -- | -- |
Front Center Speaker Output Signal (+) | 1 | 1 | 1 | -- |
Front Center Speaker Output Signal (-) | 1 | 1 | 1 | -- |
Left Front Midrange Speaker Output Signal (+) | 1 | 1 | 1 | -- |
Left Front Midrange Speaker Output Signal (-) | 1 | 1 | 1 | -- |
Left Front Subwoofer Speaker Output Signal (+) | 1 | 1 | 1 | -- |
Left Front Subwoofer Speaker Output V(-) | 1 | 1 | 1 | -- |
Left Seat Speaker Output Signal (+) | 1 | 1 | 1 | -- |
Left Seat Speaker Output Signal (-) | 1 | 1 | 1 | -- |
Right Front Midrange Speaker Output Signal (+) | 1 | 1 | 1 | -- |
Right Front Midrange Speaker Output Signal (-) | 1 | 1 | 1 | -- |
Right Front Subwoofer Speaker Output Signal (+) | 1 | 1 | 1 | -- |
Right Front Subwoofer Speaker Output Signal (-) | 1 | 1 | 1 | -- |
Right Seat Speaker Output Signal (+) | 1 | 1 | 1 | -- |
Right Seat Speaker Output Signal (-) | 1 | 1 | 1 | -- |
Audio Amplifier Ground | -- | 1, 2 | -- | -- |
CD Changer Ground | -- | 1, 3 | -- | -- |
| ||||
Circuit/System Description
The audio circuits from the radio to the CD changer, and from the CD changer to the amplifier have only a varrying A/C voltage. Each of the speaker output signal circuits (+) and (-), at the audio amplifier have a DC bias voltage that is one half of the battery voltage. When using a DMM, each of the speaker signal 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 A/C 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. In an amplified audio system, these similar AC voltage measurements may be slightly higher on the output of the amplifier, and the typical AC voltage readings at the output of the radio are less than 1V AC.
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 both rear speakers. 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
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, 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. |
Circuit/System Testing
Amplifier Circuit Malfunction
- Ignition OFF, disconnect the C1 harness connector at the audio amplifier.
- Test for less than 10 ohms between the ground circuit terminal A and ground.
- Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal H and ground.
- Disconnect the C2 harness connector at the CD changer.
- Radio ON, test for a varying mV AC voltage between the appropriate signal circuit terminals listed below and ground.
- Ignition OFF, reconnecct the C2 harness connector.
- Disconnect the C2 harness connector at the audio amplifier.
- Radio ON, test for a varying mV AC voltage between the following signal circuit terminals listed below and ground.
- If all circuits test normal, replace the audio amplifier.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the circuit fuse is open, replace the audio amplifier. |
| • | Left low level audio signal (+) terminal 4 |
| • | Right low level audio signal (+) terminal 5 |
| • | Left low levelaudio signal (-) terminal 14 |
| • | Right low level audio signal (-) terminal 15 |
| ⇒ | If the varrying mV A/C voltage is not present, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the radio. |
| • | Left low level audio signal (+) terminal B10 |
| • | Left low level audio signal (-) terminal B9 |
| • | Right low level audio signal (+) terminal B11 |
| • | Right low level audio signal (-) terminal B8 |
| ⇒ | If the varrying mV A/C voltage is not present, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the CD Changer. |
Speaker Circuit Malfunction
- Disconnect the C2 harness connector at the audio amplifier.
- Radio ON, test for a varying mV AC voltage between the following signal circuit terminals listed below and ground.
- Ignition OFF, connect the C2 harness connector at the audio amplifier.
- Disconnect the harness connector at the inoperative speaker.
- Radio ON, test for 5.0-7.5 volts between the signal circuit terminal A and ground.
- Test for 5.0-7.5 volts between the signal circuit terminal B (speaker) or terminal C (subwoofer) and ground.
- If all circuits test normal, replace the appropriate speaker.
| • | Left low level audio signal (+) terminal B10 |
| • | Left low level audio signal (-) terminal B9 |
| • | Right low level audio signal (+) terminal B11 |
| • | Right low level audio signal (-) terminal B8 |
| ⇒ | If the varrying mV A/C voltage is not present, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the CD Changer. |
| ⇒ | 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 audio amplifier. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the audio amplifier. |
| ⇒ | 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 audio amplifier. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the audio amplifier. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for Audio Amplifier and Radio replacement, setup, and programming |
