Pinpoint Test B: Poor Quality/Distorted/No Sound from One Or More Speakers (Not All Speakers) - Except Subwoofers

Information and Entertainment System

Pinpoint Tests

Pinpoint Test B: Poor Quality/Distorted/No Sound from One or More Speakers (Not All Speakers) - Except Subwoofers

Refer to Wiring Diagram Set 130, Audio System/Navigation for schematic and connector information. Diagrams By Number

Normal Operation

The Audio Control Module (ACM) directs the audio signals to the speakers through separate positive and negative circuits for each of the audio channels. The ACM provides internal circuit protection for shorts to ground, shorts to voltage, or shorts between any output circuits.

- DTC B2965 (Audio System Speaker Circuit Fault) - sets when an open, a short to ground, or a short to voltage is detected on the front door or rear door speaker circuits. The ACM checks these circuits during the self-test, and checks them every 500 milliseconds during normal operation.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Speaker
- ACM

PINPOINT TEST B: POOR QUALITY/DISTORTED/NO SOUND FROM ONE OR MORE SPEAKERS (NOT ALL SPEAKERS) - EXCEPT SUBWOOFERS

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

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B1 CHECK FOR OTHER CONCERNS


- Ignition OFF.
- Remove the trim panel for the suspect speaker.
- Remove the speaker and check for:
- connector integrity
- debris in the speaker cone
- Install the speaker, but leave the trim panel off.
- Ignition ON.
- Operate the audio system in radio tuner (AM/FM) mode.
- Observe the operation of the suspect speaker.
- Is the speaker sound OK?

Yes
INSPECT the trim panel and REPAIR as necessary. TEST the system for normal operation.

No
GO to B2.

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B2 CHECK THE SPEAKER CIRCUITS FOR VOLTAGE


- Ignition OFF.
- Disconnect: Suspect Speaker.
- Ignition ON.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the suspect speaker pin 1 and pin 2, harness side as follows:





- Is an alternating AC voltage present?

Yes
INSTALL a new speaker for the suspect speaker. REFER to Door Speaker Door Speaker or Quarter Panel Speaker Quarter Panel Speaker. CLEAR the DTCs. REPEAT the speaker walk-around test.

No
GO to B3.

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B3 CHECK THE SPEAKER CIRCUITS FOR A SHORT TO VOLTAGE


- Ignition OFF.
- Disconnect: ACM C290d.
- Ignition ON.
- Measure the voltage between the suspect speaker, harness side and ground as follows:





- Is any voltage present?

Yes
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the speaker walk-around test.

No
GO to B4.

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B4 CHECK THE SPEAKER CIRCUITS FOR AN OPEN OR SHORT TO GROUND


- Ignition OFF.
- Measure the resistance between the suspect speaker, harness side and the ACM, harness side; and between the suspect speaker, harness side and ground as follows:





- Is the resistance less than 5 ohms between the suspect speaker and the ACM, and greater than 10,000 ohms between the suspect speaker and ground?

Yes
GO to B5.

No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the speaker walk-around test.

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B5 CHECK FOR CORRECT ACM OPERATION


- Disconnect all the ACM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the ACM connectors and make sure they seat correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?

Yes
INSTALL a new ACM. REFER to Audio Control Module (ACM) Removal and Replacement. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.

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