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.
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.
Does the self-diagnostic function indicate a VSP signal?
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 -
- Without USB adapter and climate control: Go to step 4.
- With USB adapter or without USB adapter, with climate control: 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/indication goes away, replace the original audio unit Audio Unit Removal/Installation.
4. Turn the ignition switch to LOCK (0).
5. Jump the SCS line with the HDS.
6. Disconnect PCM connector A (49P).
7. Turn the ignition switch to ON (II).
8. Measure the voltage between audio-navigation unit connector A (24P) terminal No. 15 and body ground.
Is there about 5.0 V?
YES -
Go to step 9.
NO -
Substitute a known-good audio Audio Unit Removal/Installation, and recheck. If the symptom/indication goes away, replace the original audio Audio Unit Removal/Installation.
9. Connect PCM connector A (49P).
10. Drive the vehicle, and have an assistant measure the voltage between audio unit connector A (24P) terminal No. 15 and body ground.
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 -
Replace the audio unit Audio Unit Removal/Installation.
NO -
Repair an open or a short in the wire between audio unit connector A (24P) terminal No. 15 and PCM connector A (49P) terminal No. 30. If no open or short is found, update the PCM PCM Update if it does not have the latest software, or substitute a known-good PCM.