Radio Volume Is Low Or Interference Noise Occurs

Probable cause:

Reception environment, antenna circuit malfunction, influence by external devices, ground circuit malfunction, unit body malfunction

Wiring diagram:

Audio system Ref. to WIRING SYSTEM (IMPREZA MODEL)>AUDIO SYSTEM>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>AUDIO SYSTEM>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>AUDIO SYSTEM>WIRING DIAGRAM .
Navigation system Ref. to WIRING SYSTEM (IMPREZA MODEL)>NAVIGATION SYSTEM>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>NAVIGATION SYSTEM>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>NAVIGATION SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION:

If non-genuine electrical parts are installed, they may cause interference noise.
Refer to the following diagnostic procedure if equipped with the digital radio using the Internet connection.
Check SUBARU STARLINK service: Ref. to INFOTAINMENT (DIAGNOSTICS)>DIAGNOSTICS WITH PHENOMENON>INSPECTION>CHECK SUBARU STARLINK SERVICE .
Bluetooth connection cannot be established: Ref. to INFOTAINMENT (DIAGNOSTICS)>DIAGNOSTICS WITH PHENOMENON>INSPECTION>BLUETOOTH CONNECTION CANNOT BE ESTABLISHED .
Check connection between smartphone and unit: Ref. to INFOTAINMENT (DIAGNOSTICS)>DIAGNOSTICS WITH PHENOMENON>INSPECTION>CHECK CONNECTION BETWEEN SMARTPHONE AND UNIT .
Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to INFOTAINMENT (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION .

NOTE: When the volume of AHA and Pandora is low, connect the smartphone to the Internet, and check that AHA and Pandora is audible on the smartphone itself. When it is inaudible, or the volume is too low, there is a problem with the smartphone, Internet connection or service provider. When it is audible with the smartphone without any troubles, there is a problem with connection to the vehicle (USB connection or Bluetooth connection).

CHECK SYMPTOM .
Check in which condition (place) the noise occurs.

Does it occur in any places?

Yes: Go to 2.

No: Radio wave reception condition is poor. (In tunnel, buildings, etc.) There is no failure on the vehicle.
CHECK ANTENNA .
Check for poor contact of connectors or terminals.

Is the check result OK?

Yes: Go to 3.

No: Repair or replace the harness.
CHECK HARNESS .
Check the antenna harness for an open or short circuit, and check the booster.

Is the check result OK?

Yes: Go to 4.

No: Repair or replace the harness.
CHECK UNIT GROUND CIRCUIT .
Check the unit ground connector (1P on back side).

Is the check result OK?

Yes: Go to 5.

No: Repair or replace the ground circuit.
CHECK ENVIRONMENTAL CONDITION .
Check if any external devices which emit strong electromagnetic waves and noises, such as a radio antenna, is installed inside the vehicle.

Is the check result OK?

Yes: Go to 6.

No: Remove the external device. There is no failure if it returns to normal. If the fault is not fixed: Go to 6.
CHECK NOISE OCCURRENCE CONDITION .
Stop the engine, and with the ignition switch ON, check for noise occurrence.

Does the noise occur while the engine stops?

Yes: Replace the audio or navigation unit. Ref. to ENTERTAINMENT & MONITORING>AUDIO . Ref. to ENTERTAINMENT & MONITORING>NAVIGATION BODY .

No: Check that the engine ignition system, generator, engine ground circuit and chassis ground circuit are connected securely.