Volume Does Not Increase With Speed (Without Navigation and Multi-Information Display)

Audio System Symptom Troubleshooting - Volume does not increase with speed

Volume does not increase with speed

* Check the vehicle battery condition first Battery Test.
* Check the connectors for poor connections or loose terminals.

1. Problem verification:

Problem verification
-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- The failure is duplicated, go to step 2.

2. Determine possible failure area (audio setting, others):

Determine possible failure area (audio setting, others)
-1. Verify the SVC mode setting in the audio unit sound set-up.

Is the SVC set to off?
-YES- Change the setting to SVC MID, and recheck.
-NO- Go to step 3.

3. Determine possible failure area (audio unit, others):

Determine possible failure area (audio unit, others)
-1. Do the Self-Diagnostic Function, and use the vehicle speed pulse indication Audio System Self-Diagnostic Function.

-2. With the help of an assistant test-drive the vehicle, and watch the VSP signal.

Does the self-diagnostic function indicate a VSP signal?
-YES- Replace the audio unit Audio Unit Removal and Installation.
-NO- Go to step 4.

4. Determine possible failure area (VSP line, others):

Determine possible failure area (VSP line, others)
-1. Turn the ignition switch to LOCK (0).

-2. Jump the SCS line with the HDS.

-3. Disconnect the following connector.





-4. Turn the ignition switch to ON (II).

-5. Measure the voltage between test points 1 and 2.









Is there about 5 V?
-YES- Go to step 6.
-NO- Go to step 5.

5. Open wire check (VSP line):

Open wire check (VSP line)
-1. Measure the voltage between test points 1 and 2.









Is there about 5 V?
-YES- Repair an open in the wire between the audio unit and the ECM/PCM.
-NO- Replace the audio unit Audio Unit Removal and Installation.

6. ECM/PCM check:

ECM/PCM check
-1. Turn the ignition switch to LOCK (0).

-2. Reconnect ECM/PCM connector A (49P).

-3. Raise the vehicle on a lift.

-4. Turn the ignition switch to ON (II).

-5. Measure the voltage between test points 1 and 2.









Does the voltage pulse between 0 V and 5 V as you rotate the tires?
-YES- Replace the audio unit Audio Unit Removal and Installation.
-NO- Update the ECM/PCM ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM/PCM (R18Z1 engine) or ECM (R24Z7 engine) Service and Repair, and recheck.