Pinpoint Test AC: The Speed Sensitive Volume Does Not Operate Correctly

Information and Entertainment System

Pinpoint Tests

Pinpoint Test AC: The Speed Sensitive Volume Does Not Operate Correctly

Normal Operation

The speed sensitive volume function adjusts the volume based on the Vehicle Speed Sensor (VSS) signal from the Instrument Cluster (IC). The IC does not generate the VSS signal; it gateways the signal from the PCM. The Smart Junction Box (SJB) also receives this signal and should exhibit symptoms if the signal is lost.

This pinpoint test is intended to diagnose the following:

- Speed sensitive volume setting
- VSS signal concern
- Communication network concern
- ACM



PINPOINT TEST AC: THE SPEED SENSITIVE VOLUME DOES NOT OPERATE CORRECTLY

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AC1 CHECK THE SPEEDOMETER OPERATION


- Drive the vehicle and observe the speedometer.
- Does the speedometer operate correctly?

Yes
GO to AC2.

No
REFER to Instrument Panel, Gauges and Warning Indicators.

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AC2 CHECK THE SPEED SENSITIVE VOLUME SETTING


- Turn the speed sensitive volume off. Refer to the Owner's Literature.
- Operate the audio system in radio tuner (AM/FM) mode.
- Drive the vehicle at various speeds and observe the speaker volume.
- Set the speed sensitive volume to maximum compensation. Refer to the Owner's Literature.
- Operate the audio system in radio tuner (AM/FM) mode.
- Drive the vehicle at various speeds and observe the speaker volume.
- Does the volume remain constant with the speed sensitive volume turned off, and increase and decrease with vehicle speed with the speed sensitive volume set to maximum?

Yes
The system is operating correctly at this time. INSTRUCT the customer in the correct usage of the speed sensitive volume feature.

No
GO to AC3.

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AC3 CHECK FOR DTC U0155 OR DTC U0155:00


- Using the scan tool, retrieve all continuous DTCs.
- Is DTC U0155:00 or DTC U0155 retrieved in any module?

Yes
GO to Pinpoint Test AT. Pinpoint Test AT: DTC U0184 Or DTC U0184:00

No
GO to AC4.

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AC4 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) 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. CLEAR any DTCs present.

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