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Active Noise Cancellation Malfunction




Active Noise Cancellation 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

An active noise cancellation (ANC) system has four main components; the ANC module, microphone(s), audio amplifier(s) and speaker(s). The microphone is connected to the audio system and picks up the sound/noise in the vehicle cabin while the speakers produce the cancellation vibrations.

Reference Information
Schematic Reference

Radio/Navigation System Schematics (Radio/Navigation System Schematics)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
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 (Programming and Relearning) for scan tool information

Circuit/System Verification

1. Verify that DTCs B1025, B1035, B1045, and B1055 are not set.

• If any DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle).

2. Ignition ON, radio ON, verify that there is no low or high response test tones.

• If a response test tone is heard, refer to Diagnostic Mode Signal Circuit Testing.

3. Place the active noise cancellation module into diagnostic mode. Install a 3 A fuse jumper wire between the spare fuse 3 located in the I/P fuse block and ground.
4. Verify that a low response test tone is heard from the front speakers indicating the module has entered diagnostic mode.

• If a low response test tone is not heard, refer to Active Noise Cancellation Module and Front Speaker Circuit Testing.

5. After the low response test tone is heard from the front speakers, verify that a high response tone is heard from the front speakers.

• If a high response tone is not heard, refer to Front Microphone Circuit Testing.

6. After the high response tone is heard from the front speakers, verify that a low test tone should be heard from the rear speakers.

• If a low response test tone is not heard from the rear speakers, refer to Rear Speaker Circuit Testing.

7. After the low test response tone is heard from the rear speakers, a high response tone should be heard from the rear speakers.

• If a high response tone is not heard from the rear speakers, refer to Rear Microphone Circuit Testing.

8. If all four tones are heard, refer to Engine RPM Signal Circuit Testing.

Circuit/System Testing

Active Noise Cancellation Module and Front Speaker Circuit Testing
1. Ignition OFF, disconnect the harness connector at the active noise cancellation module.
2. Test for less than 5.0 ohm between the ground circuit terminal 11 and ground.

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

3. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.

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

4. Radio ON, test for B+ between the signal circuit terminal 2 and ground.

• If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the T3 amplifier.

5. Ignition OFF, connect the harness connector at the active noise cancellation module. Disconnect the X2 harness connector at the T3 amplifier.
6. Radio ON, test for 4-8 V between the signal circuit terminals listed below and ground.

* Front low level audio signal (+) - terminal 14
* Front low level audio signal (-) - terminal 13

• 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 active noise cancellation module.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the active noise cancellation module.

7. If all circuits test normal, replace the active noise cancellation module.

Front Microphone Circuit Testing
1. Ignition OFF, disconnect the harness connector at the active noise cancellation front microphone.
2. Ignition OFF, test for less than 5 ohm between the low reference circuit terminal A and ground.

• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the active noise cancellation module.

3. Ignition ON, test for 9-11 V between the signal circuit terminal B and ground.

• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the active noise cancellation module.
• 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 active noise cancellation module.

4. If all circuits test normal, replace the active noise cancellation front microphone.

Rear Speaker Circuit Testing
1. Ignition OFF, disconnect the X2 harness connector at the T3 amplifier.
2. Radio ON, test for 4-8 V between the signal circuit terminals listed below and ground.

* Rear low level audio signal (+) - terminal 15
* Rear low level audio signal (-) - terminal 16

• 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 active noise cancellation module.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the active noise cancellation module.

3. If all circuits test normal, replace the T3 amplifier.

Rear Microphone Circuit Testing
1. Ignition OFF, disconnect the harness connector at the active noise cancellation rear microphone.
2. Ignition OFF, test for less than 5 ohm between the low reference circuit terminal A and ground.

• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the active noise cancellation module.

3. Ignition ON, test for 9-11 V between the signal circuit terminal B and ground.

• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the active noise cancellation module.
• 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 active noise cancellation module.

4. If all circuits test normal, replace the active noise cancellation front microphone.

Engine RPM Signal Circuit Testing
1. Ignition ON, radio ON, test for 4-5 V between the signal circuit terminal 5 and ground.

• If greater then specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the active noise cancellation module.
• If less then specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the active noise cancellation module.

2. If all circuits test normal, replace the active noise cancellation module.

Diagnostic Mode Signal Circuit Testing
1. Ignition ON, radio ON, verify that the low and high response test tones are not heard.

• If the test tones are audible, test the signal circuit for a short to ground. If the circuit tests normal, replace the active noise cancellation module.

2. If all circuits test normal, replace the active noise cancellation module.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Radio Volume Compensator Interior Noise Microphone Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for radio replacement, setup, and programming

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