Volume Does Not Increase With Speed

Audio System Symptom Troubleshooting - Volume does not increase with speed

Volume does not increase with speed

NOTE:

- Check the vehicle battery condition first Testing and Inspection.
- Check the connectors for poor connections or loose terminals.

1. Test-drive the vehicle at highway speeds, and monitor if the volume increases.

Does the volume increase?

YES -

Intermittent failure, the system is OK at this time.�

NO -

Go to step 2.

2. Verify SVC mode setting in audio unit sound adjustment set-up.

Is the SVC set to off?

YES -

Change setting to SVC MID, and recheck.�

NO -

Go to step 3.

3. Do the Self-Diagnostic Function for the vehicle speed pulse indication Audio System Self-Diagnostic Function.

Does self-diagnostic function indicate a VSP signal?

YES -

Substitute a known-good audio unit; with navigation system Audio Unit Removal/Installation (With Navigation), without navigation system Audio Unit Removal/Installation (Without Navigation), and recheck. If the symptom/indication goes away, replace the original audio unit; with navigation system Audio Unit Removal/Installation (With Navigation), without navigation system Audio Unit Removal/Installation (Without Navigation).�

NO -

- 1 CD type: Go to step 4.
- Except 1 CD type: Check for B-CAN DTCs (communication BUS Line Error) with the HDS and go to the indicated DTC's troubleshooting. If no B-CAN DTCs or communication bus line errors are found, substitute a known-good audio unit; with navigation system Audio Unit Removal/Installation (With Navigation), without navigation system Audio Unit Removal/Installation (Without Navigation), and recheck. If the symptom/indication goes away, replace the original audio unit; with navigation system Audio Unit Removal/Installation (With Navigation), without navigation system Audio Unit Removal/Installation (Without Navigation).�

4. Disconnect audio unit connector A (24P).

NOTE: Eject all the CDs before removing the audio unit and CD changer to prevent damaging the CD player's load mechanism.

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

6. Test-drive the vehicle and have an assistant measure the voltage at between audio unit connector A (24P) terminal No. 15 and body ground.

NOTE: Some volt meters may show an average of 2.5 V, and others may show a constant voltage, depending on the meter's measurement speed.





Is there a 0-5 V pulse?

YES -

Substitute a known-good audio unit Audio Unit Removal/Installation (Without Navigation), and recheck. If the symptom/indication goes away, replace the original audio unit Audio Unit Removal/Installation (Without Navigation).�

NO -

Repair an open or a short in the wire between the audio unit connector A (24P) terminal No. 15 and the ECM/PCM connector A (49P) terminal No. 30. If no opens are found, update the ECM/PCM ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM/PCM.�