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Audio System Symptom Troubleshooting - USB audio device input sound is low or cannot be heard

USB audio device input sound is low or cannot be heard
NOTE:
  • Check the vehicle battery condition first.
  • Check the connectors for poor connections or loose terminals.
  1. Turn the ignition switch to ON (II).
Do all speakers make a sound?
YES -
Go to Step 3 .
NO -
Go to no sound is heard from speaker(s).■
  1. Turn the ignition switch to LOCK (0).
  1. Connect the customer′ s USB device to a known-good vehicle that equipped with the USB adapter and check the USB device operation.
Is the USB device working properly?
YES -
Go to Step 5 .
NO -
USB device is faulty. Also check the USB cable and USB adapter connector condition.■
  1. On the customer′s vehicle, connect the customer′s USB device to the USB adapter.
  1. Turn the ignition switch to ON (II) and turn on the audio unit.
  1. Check if the USB device can be operated with the audio unit (Folders or Files UP/DOWN, etc.).
Can the USB device be operated but no sound is heard?
YES -
Go to Step 8 .
NO -
If the sound is normal, USB device is OK at this time. If the USB device cannot be operated, Go to USB audio device does not work.
  1. Turn the ignition switch to LOCK (0).
  1. Disconnect audio unit connector C (14P).
  1. Disconnect USB adapter unit connector A (14P).
  1. Check for continuity between the terminals of audio unit connector C (14P) according to the table.
    From terminal(wire color)
    To terminals(wire color)
    C4 (PNK)
    C5 (BRN), C6 (WHT), C13 (RED), C14 (LT BLU)
    C5 (BRN)
    C6 (WHT), C13 (RED), C14 (LT BLU)
    C6 (WHT)
    C13 (RED), C14 (LT BLU)
    C13 (RED)
    C14 (LT BLU)

Is there continuity between any of the terminals?
YES -
Short in the wires between audio unit and USB adapter unit. Replace the affected shielded harness.■
NO -
Go to Step 12 .

  1. Check for continuity between audio unit connector C (14P) and USB adapter unit connector A (14P) according to the table.
    Audio unit connector
    USB adapter unit connector
    Wire color
    C5
    A5
    BRN
    C6
    A6
    WHT
    C13
    A13
    RED
    C14
    A14
    LT BLU

Is there continuity?
YES -
Substitute a known-good USB adapter unit, then reconnect all of the connectors and recheck. If the symptom/indication goes away, replace the original USB adapter unit. If the symptom/indication is still present, replace the audio unit.■
NO -
Open in the wire(s) between the audio unit and the USB adapter unit. Replace the affected shielded harness.■