Volume does not increase with speed (with navigation)

WARNING: This page is about a different car, the 2011 Honda Insight and 2010 Honda Insight. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

Check the vehicle battery condition first (see 12 VOLT BATTERY TEST ).
Check the connectors for poor connections or loose terminals.

Verify SVC mode setting in the audio-navigation unit sound set-up.
Is the SVC set to off?

YES -Change the setting to MID, and retest.

NO -go to step 2.
Enter the navigation diagnostic mode, and use the Car status diagnosis to check the vehicle speed pulse signal (see YAW RATE TUNING ).
Is there a vehicle speed signal OK?

YES -Substitute a known-good audio-navigation unit (see AUDIO-NAVIGATION UNIT REMOVAL/INSTALLATION ), and retest. If the symptom/indication goes away, replace the original audio-navigation unit.

NO -go to step 3.
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 4.
Turn the ignition switch to LOCK (0).
Remove the audio-navigation unit (see AUDIO-NAVIGATION UNIT REMOVAL/INSTALLATION ), and disconnect audio-navigation unit connector A (24P).
NOTE:
- Eject all the discs before removing the audio-navigation unit to prevent damaging the CD player's load mechanism.
- Remove the PC card before removing the audio-navigation unit.
Turn the ignition switch to ON (II).
Drive the vehicle, and have an assistant measure the voltage at audio-navigation unit connector A (24P) terminal No. 15 and body ground.
NOTE: Some voltmeters may show an average of 2.5V, and others may show a constant voltage, depending on the meter's measurement speed.

Fig 1: Measuring Voltage At Audio-Navigation Unit Connector A (24P) Terminal No. 15 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there a 0-5 V pulse or about 2.5 V average?

YES -Substitute a known-good audio-navigation unit (see AUDIO-NAVIGATION UNIT REMOVAL/INSTALLATION ), and recheck. If the symptom/indication goes away, replace the original audio-navigation unit.

NO -Repair an opens or a shorts in the wire between audio-navigation unit connector A (24P) terminal No. 15 and PCM connector A (44P) terminal No. 29. If no opens are found, substitute a known-good PCM (see SUBSTITUTING THE PCM ), and recheck. If the symptom/indication goes away, replace the original PCM (see PCM INPUTS AND OUTPUTS AT PCM CONNECTOR A ( ) (44P) ).