Volume Does Not Increase With Speed (Without Navigation)

Audio System Symptom Troubleshooting - Volume does not increase with speed

Volume does not increase with speed (without navigation)

NOTE:

- Check the vehicle battery condition first Battery Test.
- Check the connectors for poor connections or loose terminals.
- Set the fader and balance positions to the center.

1. Check the SVC mode setting in the audio-navigation unit or audio unit sound setup.

Is the SVC set to off?

YES -

Change the setting to at least the MID setting, and retest.

NO -

Go to step 2.

2. Do the self-diagnostic function for the vehicle speed pulse indication (VSP) Initial Inspection and Diagnostic Overview.

Does the self-diagnostic function indicate a VSP signal when the vehicle is moving?

YES -

Substitute a known-good audio unit Audio Unit Removal/Installation and retest. If the symptom/indication goes away, replace the original audio unit Audio Unit Removal/Installation.

NO -

Go to step 3.

3. Test-drive the vehicle at highway speeds, and monitor if the volume increases with speed.

Does the volume increase?

YES -

Intermittent failure, the system is OK at this time.

NO -

Go to step 4.

4. Remove the audio unit Audio Unit Removal/Installation, and disconnect audio unit connector A (24P).

5. Raise the vehicle on a lift.

6. Turn the ignition switch to ON (II).

7. Press the brake pedal, and shift the transmission to N.

8. Slowly spin one of the front wheels by hand, and have an assistant measure the voltage at audio unit connector A (24P) terminal No. 15.





Is there a 0-5 V pulse?

YES -

Replace the audio unit Audio Unit Removal/Installation.

NO -

Repair an open or short in the wire between audio unit connector A (24P) terminal No. 15 and ECM/PCM connector A (44P) terminal No. 30. If no open or short is found, substitute a known-good ECM/PCM, and recheck. If the symptom/indicated goes away, replace the original ECM/PCM Service and Repair.