Note. Check the vehicle battery condition first (see BATTERY TEST ). Check the connectors for poor connections or loose terminals. Set the fader and balance positions to the center.
- Check the (SVC) mode setting in the audio unit sound set-up. Is the (SVC) set to off? YES -Change the setting to at least the Mid setting, and retest. NO -Go to step 2.
- Do the self-diagnostic function for the vehicle speed pulse indication (see «SELF-DIAGNOSTIC FUNCTION»(ref-510484-S18298400512012102300000) ). Does the self-diagnostic function indicate a VSP signal when the vehicle is moving? YES -Substitute a known-good audio unit (see «AUDIO UNIT REMOVAL/INSTALLATION»(ref-510484-S38675893192012102300000) ), and recheck. If the symptom/indication goes away, replace the original audio unit (see «AUDIO UNIT REMOVAL/INSTALLATION»(ref-510484-S38675893192012102300000) ). 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 -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 (see «AUDIO UNIT REMOVAL/INSTALLATION»(ref-510484-S38675893192012102300000) ), and recheck. If the symptom goes away, replace the original audio unit (see «AUDIO UNIT REMOVAL/INSTALLATION»(ref-510484-S38675893192012102300000) ).