Volume Does Not Increase With Speed

Volume does not increase with speed

1. Verify the (SVC) mode setting in the navigation or audio unit sound set-up.

Is the (SVC) set to off?

YES - Change the setting to "Mid" 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?

YES - Substitute a known-good navigation or audio unit and retest. If the symptom/indication goes away, replace the original navigation or audio unit.

NO - Go to step 3.

3. Test-drive the vehicle at highway speeds, and monitor if the volume increases with speed.

Do the volume increase?

YES - Intermittent failure, the system is OK at this time.

NO - Go to step 4.

4. Remove the navigation unit, or audio unit, and disconnect the navigation, or audio unit connector A (17P).
5. Raise the vehicle on a lift.
6. Turn the ignition switch ON (II).
7. Press the brake pedal, and shift the transmission to D.




8. Slowly spin one of the front wheels by hand, and have an assistant measure voltage at navigation or audio unit connector A (17P) terminal No. 13.

Is the O-5 V pulse?

YES -
- With navigation: Replace the navigation unit.
- Without navigation: Replace the audio unit.

NO - Repair open or shorts in the wire between the navigation, or audio unit connector A (17P) No. 13 terminal and the PCM connector A (44P) No. 29 terminal. If no opens or shorts are found, substitute a known-good PCM and recheck. If the symptom/indicated goes away, replace the original PCM.