Pinpoint Test B: No Sound From All Speakers

Information and Entertainment System

Pinpoint Tests

Pinpoint Test B: No Sound From All Speakers

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

Normal Operation

When the key is in START, the Audio Control Module (ACM) receives voltage through the start mute circuit to prevent voltage spikes from producing a popping noise through the speakers. However, a short to voltage on this circuit causes the ACM output to be continuously muted. It also causes the voice recognition to be inoperative.

If the ACM loses power or ground, the scan tool cannot communicate with it. Refer to Module Communications Network Testing and Inspection to continue diagnosis.

If DTC B2965 is set in the ACM, the cause of the concern is a short to ground or short to voltage in the circuitry to an individual speaker, which has caused the ACM overload protection to activate. If DTC B2965 is present, GO to Pinpoint Test C. Pinpoint Test C: 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 B: 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.

-------------------------------------------------
B1 CHECK THE AUDIO DISPLAY


- Operate the audio system in radio tuner (AM/FM) mode.
- Observe the audio display on the Front Display Interface Module (FDIM).
- Does the audio display operate correctly?

Yes
GO to B2.

No
GO to Pinpoint Test A. Pinpoint Test A: The Entire Audio System is Inoperative

-------------------------------------------------
B2 CHECK THE START SENSE CIRCUIT FOR A SHORT TO VOLTAGE


- Ignition OFF.
- Disconnect: ACM C240a.
- 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 B3.

-------------------------------------------------
B3 CHECK FOR CORRECT ACM OPERATION


- Ignition OFF.
- 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) 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.

-------------------------------------------------