Speaker Malfunction
Speaker Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
Each of the audio output channel circuits (+) and (-) at the radio and amplifier have a varying AC voltage. Each of the audio output channel circuits at the audio amplifier also have a DC bias voltage that is approximately one half of battery voltage. 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. Both the DC bias voltage and the AC voltage signals are needed for the speakers to properly produce sound. The frequency (Hz) of the AC voltage signal is directly related to the frequency of the input (audio source playing) to the audio system. The AC voltage will vary depending on what type of audio is being listened to, as well as the volume setting of the system.
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.
The EL-50334-6 Audio System Diagnostic CD contains audio tracks that can be used to duplicate and isolate such concerns. Tracks 11 and 12 contain audio sweep tones for testing for speaker and grill rattles.
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.
* Tune the radio to different audio sources in order to verify that the speaker concern is not caused by a different malfunctioning system.
Reference Information
Schematic Reference
Radio/Navigation System Schematics Radio/Navigation System Schematics
Connector End View Reference
Component Connector End Views Folding Top 5 Bow Lowered Switch (CM7)
Description and Operation
Radio/Audio System Description and Operation Radio/Audio System
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References 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 not heard from all speakers, or the audio emitted from the speakers is not clear, refer to Circuit/System Testing.
Circuit/System Testing
With U65
1. Ignition OFF, disconnect the X1 harness connector at the audio amplifier.
2. Test for less than 10 ohms between the ground circuit terminal 8 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Test for B+ between the B+ circuit terminal 4 and ground.
• If less than 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. Ignition ON, radio ON, mute OFF, test for B+ between the antenna enable signal circuit terminal 8 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 less than 1 V between the amplifier mute signal terminal 11 and ground.
• If greater than the specified value, test the mute signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
7. Mute ON, test for 4.75-5.25 V between the amplifier mute signal terminal 11 and ground.
• If less than the specified range, test the mute 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 mute signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
8. Radio ON, mute OFF, test for a varying AC mV reading between the following signal circuit terminals listed below and ground.
* Left front low level audio signal (+) terminal 15
* Left front low level audio signal (-) terminal 7
* Right front low level audio signal (+) terminal 14
* Right front low level audio signal (-) terminal 6
* Left rear low level audio signal (+) terminal 13
* Left rear low level audio signal (-) terminal 5
* Right rear low level audio signal (+) terminal 12
* Right rear low level audio signal (-) terminal 4
• If not the specified value, 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.
9. Ignition OFF, reconnect all harness connectors at the amplifier.
10. Disconnect the harness connector at the appropriate speaker.
11. Ignition ON, radio ON, test for 4-8 V between the control circuit terminals listed below and ground:
* Speaker control (-) - terminal A
* Speaker control (+) - terminal B
• If less than the specified range, test both circuits of the affected speaker for a short to ground. If the circuit tests normal, replace the audio amplifier.
• If greater than the specified range, test both circuits of the affected speaker for a short to voltage. If the circuit tests normal, replace the audio amplifier.
12. Test for a varying AC mV reading between the following signal circuit terminals listed below and ground:
* Speaker control (-) - terminal A
* Speaker control (+) - terminal B
• If not the specified value, replace the audio amplifier.
13. If all circuits test normal, replace the appropriate speaker.
With U66
1. Ignition OFF, disconnect the X1 harness connector at the audio amplifier.
2. Test for less than 10 ohms between the ground circuit terminal F and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Test for B+ between the B+ circuit terminal E and ground.
• If less than the specified value, test the B+ circuit for a short to ground or an open/high resistance.
4. Disconnect the X2 harness connector at the audio amplifier.
5. Ignition ON, radio ON, mute OFF, test for B+ between the antenna enable signal circuit terminal A3 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 less than 1 V between the amplifier mute signal terminal A8 and ground.
• If greater than the specified value, test the mute signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
7. Mute ON, test for 4.75-5.25 V between the amplifier mute signal terminal A8 and ground.
• If less than the specified range, test the mute 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 mute signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
8. Radio ON, mute OFF, test for a varying AC mV reading between the following signal circuit terminals listed below and ground.
* Left front low level audio signal (+) terminal A7
* Left front low level audio signal (-) terminal A6
* Right front low level audio signal (+) terminal B6
* Right front low level audio signal (-) terminal B7
* Left rear low level audio signal (+) terminal A4
* Left rear low level audio signal (-) terminal A5
* Right rear low level audio signal (+) terminal B5
* Right rear low level audio signal (-) terminal B4
• If not the specified value, 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.
9. Ignition OFF, reconnect all harness connectors at the amplifier.
10. Disconnect the harness connector at the appropriate speaker.
11. Ignition ON, radio ON, test for 4-8 V between the control circuit terminals listed below and ground:
* Speaker control (-) - terminal A
* Speaker control (+) - terminal B
• If less than the specified range, test both circuits of the affected speaker 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 both circuits of the affected speaker for a short to voltage. If the circuit tests normal, replace the audio amplifier.
12. Test for a varying AC mV reading between the following signal circuit terminals listed below and ground:
* Speaker control (-) - terminal A
* Speaker control (+) - terminal B
• If not the specified value, replace the audio amplifier.
13. If all circuits test normal, replace the appropriate speaker.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Speaker Replacement Reference Speaker Replacement Reference
* Control Module References Control Module References for Audio Amplifier or Radio replacement, programming and setup