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. Turn the ignition switch to ON (II).
2. Verify the SVC mode setting in the audio unit sound set-up.

Is the SVC set to off?

YES - Change the setting to Mid and reset.

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. Turn the ignition switch to LOCK (0).
5. Remove the audio-HVAC display module assembly, and disconnect audio unit connector C (40P).
6. Raise the front of the vehicle, make sure it is securely supported, and allow the front wheels to rotate freely. Or raise the vehicle on a lift.
7. Turn the ignition switch to ON (II).
8. Press the brake pedal, and shift the transmission to D.
9. Slowly spin one of the front wheels by hand, and have an assistant measure voltage at navigation or audio unit connector C (40P) terminal No. 26 while the front wheels are rotating.






Is there a 0-5 V pulse?

YES - Replace the audio unit.

NO - Repair open or shorts in the wire between the audio unit connector C (40P) No. 26 terminal and the ECM/PCM connector E (31P) No. 11 terminal. If no opens or shorts are found, substitute a known-good ECM/PCM and recheck. If the symptom/indicated goes away, replace the original ECM/PCM.