Pinpoint Test AD: Poor Quality/Distorted/No Sound From All Speakers

Information and Entertainment System

Pinpoint Tests

Pinpoint Test AD: Poor Quality/Distorted/No Sound From All Speakers

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

Normal Operation

The Audio Control Module (ACM) sends an analog signal to the speakers or to the Rear Entertainment Module (RETM), depending on vehicle configuration.

When the ACM detects voltage on circuit CBP28 (GY/VT) with the ignition in START, it mutes all speaker output to prevent a popping noise in the speakers during engine cranking. However, a short to voltage on this circuit will cause the ACM to continuously mute the audio output.

In addition, a short to ground or voltage on any of the speaker circuits may cause the overload protection feature of the ACM to activate. When this happens, the ACM stops sending audio signals, resulting in no sound from all speakers. If a short to ground or voltage occurs, DTC B2965 will set. If DTC B2965 is present, Go To Pinpoint Test B. Pinpoint Test B: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers)

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- ACM



PINPOINT TEST AD: POOR QUALITY/DISTORTED/NO SOUND FROM ALL SPEAKERS

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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AD1 CHECK FOR ACM DTCs


- Carry out the ACM self-test using the scan tool.
- Is DTC B2965 present?

Yes
Go To Pinpoint Test B. Pinpoint Test B: Poor Quality/Distorted/No Sound From One Or More Speakers (Not All Speakers)

No
GO to AD2.

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AD2 CHECK CBP28 (GY/VT) FOR A SHORT TO VOLTAGE


- Ignition OFF.
- Disconnect: ACM C240a.
- With the ignition in any position except START, measure the voltage between the ACM C240a-15, circuit CBP28 (GY/VT), harness side and ground.




- Is any voltage present?

Yes
REPAIR the circuit. TEST the system for normal operation.

No
GO to AD3.

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AD3 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.
- Is the concern still present?

Yes
INSTALL a new ACM. REFER to Audio Control Module (ACM) Audio Control Module (ACM). 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.

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