Volume Does Not Increase With Speed

Symptom Troubleshooting: Volume does not increase with speed

Volume does not increase with speed

NOTE:

- Check the vehicle battery condition first.

- 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 MID, and retest.

NO - Go to step 3.


3. Do the self-diagnostic function for the vehicle speed pulse indication. Initial Inspection and Diagnostic Overview

Does self-diagnostic function indicate a VSP signal?
YES - Substitute a known-good audio unit with navigation, Audio Unit Removal/Installation (With Navigation) without navigation, Audio Unit Removal/Installation (Without Navigation) and retest. If the symptom/indication goes away, replace the original audio unit with navigation, Audio Unit Removal/Installation (With Navigation) without navigation. 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, Audio Unit Removal/Installation (With Navigation) without navigation, Audio Unit Removal/Installation (Without Navigation) and recheck. If the symptom goes away, replace the original audio unit with navigation, Audio Unit Removal/Installation (With Navigation) without navigation. Audio Unit Removal/Installation (Without Navigation)



4. Remove the audio unit with navigation, Audio Unit Removal/Installation (With Navigation) without navigation, Audio Unit Removal/Installation (Without Navigation) and 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 audio unit connector A (24P) terminal No. 15.
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 with navigation, Audio Unit Removal/Installation (With Navigation) without navigation, Audio Unit Removal/Installation (Without Navigation) and recheck. If the symptom/indication goes away, replace the audio unit with navigation, Audio Unit Removal/Installation (With Navigation) without navigation. Audio Unit Removal/Installation (Without Navigation)

NO - Repair opens or shorts 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, substitute a known-good ECM/PCM, Initial Inspection and Diagnostic Overview and recheck. If the symptom/indicated goes away, replace the original ECM/PCM. Service and Repair