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.
- Set the fader and balance positions to the center.

1. Check the (SVC) mode setting in the audio unit sound set-up.

Is the (SVC) set to off?

YES -

Change the setting to at least the Mid setting, and reset.�

NO -

Go to step 2.

2. Do the self-diagnostic function for the vehicle speed pulse indication.

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 -

- 1 CD type: Go to step 3.
- 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 Audio Unit Removal/Installation, and recheck. If the symptom goes away, replace the original audio unit Audio Unit Removal/Installation.�

3. Remove the audio unit Audio Unit Removal/Installation.

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

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

5. Test-drive the vehicle very slowly and have an assistant measure the voltage at audio unit connector A (24P) terminal No. 15.

NOTE: Some voltmeters 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 or about 2.5 V average?

YES -

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

NO -

Repair an open or a short in the wire between the audio unit connector A (24P) terminal No. 15 and the PCM connector A (49P) terminal No. 30. If no open or short is found, substitute a known-good audio unit Audio Unit Removal/Installation, and recheck. If the symptom/indication goes away, replace the original audio unit Audio Unit Removal/Installation. If the symptom does not go away, update the PCM PCM Update if it does not have the latest software or substitute a known-good PCM.�