Pinpoint Test O: The Speed Sensitive Volume Does Not Operate Correctly (Late Build Premium Audio)
Information and Entertainment System
Pinpoint Test O: The Speed Sensitive Volume Does Not Operate Correctly (Late Build Premium Audio)
Refer to Wiring Diagrams Set 130, Audio/Navigation for schematic and connector information. Electrical Diagrams
Normal Operation
The speed sensitive volume function adjusts the volume based on the Vehicle Speed Sensor (VSS) signal from the Instrument Panel Cluster (IPC). The IPC (Instrument Panel Cluster) does not generate the VSS (Vehicle Speed Sensor) signal, but rather receives it from the PCM and conveys it to the ACM (Audio Front Control Module) by means of a dedicated circuit. The GEM (Generic Electronic Module) also receives this signal and should exhibit symptoms if the signal is lost. If the ACM (Audio Front Control Module) does not receive this signal, vehicle speed compensated volume will be set to 0 MPH and no audio adjustment will be made.
- DTC C1992 (Vehicle Speed Circuit Failure)- sets when the ACM (Audio Front Control Module) detects an open or short to ground on the vehicle speed output circuit during an on-demand self-test with the ignition in the RUN or ACC position.
This pinpoint test is intended to diagnose the following:
- Speed sensitive volume setting
- VSS (Vehicle Speed Sensor) signal concern
- Network communication concern
- ACM (Audio Front Control Module)
PINPOINT TEST O : THE SPEED SENSITIVE VOLUME DOES NOT OPERATE CORRECTLY (LATE BUILD PREMIUM AUDIO)
O1 CHECK THE SPEEDOMETER OPERATION
- Drive the vehicle and observe the speedometer.
Does the speedometer operate correctly?
Yes
GO to O2.
No
REFER to Instrument Panel, Gauges and Warning Indicators.
O2 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 how to correctly use the speed sensitive volume feature.
No
GO to O3.
O3 CHECK THE VEHICLE SPEED SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM (Audio Front Control Module) C290A.
- Disconnect: IPC (Instrument Panel Cluster) C220B.
- Ignition ON.
- Measure the voltage between the ACM (Audio Front Control Module) C290A-14, circuit 4-GB10 (GY/OG), harness side and ground.
Is any voltage present?
Yes
REPAIR the circuit. TEST the system for normal operation.
No
GO to O4.
O4 CHECK THE VEHICLE SPEED SIGNAL CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the ACM (Audio Front Control Module) C290A-14, circuit 4-GB10 (GY/OG), harness side and the IPC (Instrument Panel Cluster) C220B-4, circuit 4-GB10 (GY/OG), harness side; and between the ACM (Audio Front Control Module) C290A-14, circuit 4-GB10 (GY/OG), harness side and ground.
Are the resistances less than 3 ohms between the ACM (Audio Front Control Module) and IPC (Instrument Panel Cluster), and greater than 10,000 ohms between the ACM (Audio Front Control Module) and ground?
Yes
GO to O5.
No
REPAIR the circuit. TEST the system for normal operation.
O5 CHECK FOR CORRECT ACM (Audio Front Control Module) OPERATION
- Disconnect all the ACM (Audio Front Control Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the ACM (Audio Front Control Module) 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 (Audio Front Control Module). REFER to 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.