• 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.

For symptom byte information refer to Symptom Byte List.

Each of the audio output channel circuits (+) and (-), at the radio have a DC bias voltage that is approximately one half of battery voltage. When using a DMM, each of the audio output channel circuits will measure approximately 6.5 V 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. The frequency (Hz) of the AC voltage signal is directly related to the frequency of the input (audio source playing) to the audio system. Both the DC bias voltage and the AC voltage signals are needed for the audio system to properly produce sound.

• Ignition is ON or in the ACC position
• The system voltage is 9-16  V
• The test is run once during radio wake up

The radio detects a short to voltage on the specified audio (+) or (–) circuit.

The radio detects a short to ground on the specified audio (+) or (–) circuit.

The radio detects an open on the specified audio (+) or (–) circuit.

High input signal is detected above a specified range on the (+) or (−) signal circuit.

High temperature condition is detected on the specified (+) or (−) signal circuit.

The radio continues to send the output signal to the speaker signal circuit with the current fault.

• A current DTC clears when the conditions for setting the DTC are no longer present and the ignition has been cycled from OFF to ON.
• A history DTC clears after 50 malfunction-free ignition cycles.

• Improper speaker mounting, loose trim, or loose connector to the speaker may cause an audible buzz or distortion. Inspect the appropriate speaker, the surrounding interior trim, and the connector for proper connection 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.
• The test tones on the CD may be copied to a USB drive or other device to use during testing.
• If the speaker or surrounding interior trim is found to be loose or improperly secured, correctly secure the item.
• If equipped with an Active Noise Cancellation system that utilizes an ANC module, the module replicates the high level audio signals from the radio to the speakers. If the module malfunctions, all the speakers may become inoperable.

Radio/Navigation System Schematics

Master Electrical Component List

Radio/Audio System Description and Operation

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Control Module References for scan tool information

1. Ignition ON, A11 Radio ON, mute OFF.
2. Verify clear audio is heard from each speaker, adjusting fade and balance controls to test each speaker individually.
• If audio is inoperative from one or more speakers but not all.

  Refer to Circuit/System Testing One Speaker.

• If audio is Inoperative from all speakers.

  Refer to Circuit/System Testing All Speakers.

• If clear audio is heard from all speakers.
3. All OK.

Note: Some circuits supply audio signals to more than one speaker. It may be necessary to disconnect all speakers on the affected audio circuit when performing circuit tests.

1. Ignition OFF, disconnect the harness connector at the appropriate P19 Speaker. Ignition ON, A11 Radio ON, mute OFF.
2. Test for 5–7 V between each audio signal circuit terminal 1 and terminal 2 and ground.
• If less than 5 V
1. Ignition OFF, disconnect the appropriate harness connector at the K108 Active Noise Cancellation Module / T3 Audio Amplifier.
2. Test for infinite resistance between the appropriate signal circuits and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 Ω in the signal circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the K108 Active Noise Cancellation Module / T3 Audio Amplifier.
• If greater than 7 V
1. Ignition OFF, disconnect the appropriate harness connector at the K108 Active Noise Cancellation Module / T3 Audio Amplifier. Ignition ON, A11 Radio ON, mute OFF. Test for less than 1 V between the appropriate signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K108 Active Noise Cancellation Module / T3 Audio Amplifier.
• If between 5–7 V
3. Ignition OFF, disconnect the appropriate harness connector at the K108 Active Noise Cancellation Module / T3 Audio Amplifier.
4. Ignition ON, A11 Radio ON, mute OFF. Test for 5–7 V between each appropriate audio signal circuit from the A11 Radio and Ground.
• If less than 5 V
1. Ignition OFF, Disconnect the appropriate harness connector at the A11 Radio.
2. Test for infinite resistance between the signal circuits and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 Ω in the signal circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the A11 Radio.
• If greater than 7 V
1. Ignition OFF, disconnect the appropriate harness connector at the A11 Radio. Ignition ON.
2. Test for less than 1 V between the signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the A11 Radio.
• If between 5–7 V
5. Test or replace the P19 Speaker.

1. Ignition OFF, disconnect the X1 harness connector at the K108 Active Noise Cancellation Module / T3 Audio Amplifier.
2. Test for less than 10 Ω between the ground circuit terminal 8 and ground.
• If 10 Ω or greater
1. Test for less than 2 Ω in the ground circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, repair the open/high resistance in the ground connection.
• If less than 10 Ω
3. Verify that a test lamp illuminates between the B+ circuit terminal 4 and ground.
• If the test lamp does not illuminate
1. Remove the test lamp.
2. Test for less than 2 Ω in the B+ circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If the test lamp illuminates
4. Ignition ON, A11 Radio ON.
5. Test for 2 V or greater between the control circuit terminal 3 and ground.
• If less than 2 V
1. Ignition OFF, disconnect the X2 harness connector at the A11 Radio.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 Ω in the control circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the A11 Radio.
• If 2 V or greater
6. Test for 5–7 V between any audio signal circuit from the A11 Radio and Ground.
• If not between 5–7 V

  Test or replace the A11 Radio.

• If between 5–7 V
7. Replace the K108 Active Noise Cancellation Module / T3 Audio Amplifier.

Perform the Diagnostic Repair Verification after completing the repair.

• Speaker Replacement Reference
• Control Module References for radio and amplifier replacement, programming, and setup.