ATTENTION:
GENERAL MANAGER

q

PARTS MANAGER

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CLAIMS PERSONNEL

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IMPORTANT - All
Service Personnel
Should Read and
Initial in the boxes
provided, right.

SERVICE MANAGER

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© 2025 Subaru of America, Inc. All rights reserved.

SERVICE BULLETIN
APPLICABILITY:

SUBJECT:

2025 WRX
2025 Forester Hybrid

NUMBER:
DATE:

15-326-25
06/17/25

FOTA (Firmware Over-The-Air) Reprogramming
for DENSO Gen 4.5 Audio Navigation
Infotainment Systems via DCM

INTRODUCTION:
This bulletin provides instruction for use of a new reprogramming procedure to optimize the
Denso Gen 4.5 Audio and Navigation system utilized in the models listed above. Firmware-overthe-air (FOTA) is a process where remote devices can receive updates to their operating firmware.
This process has become second nature with smartphones, tablets and many other connected
devices. FOTA for automotive infotainment systems was designed with an emphasis on customer
convenience. FOTA updates provide regular enhancements along with software patches as needed to
enhance the customer experience. The convenience factor comes not only with the supply of regular
updates and the enhancements they provide, but through customer control of when these updates are
downloaded and installed. The only requirement is a valid subscription to SUBARU STARLINK
Safety Plus, since the download of the software is performed via DCM. FOTA operation is conducted
in two steps: download (from the server to the vehicle via DCM) and installation (internal to CP1.5
system in the vehicle). This bulletin will focus on FOTA for Denso Gen 4.5 audio-navigation systems
(HIGH) which utilize the 11.6-inch touch-screen display. Models (MID) audio systems and 7-inch
dual screen display (Base) are not eligible for this FOTA update.
This bulletin outlines the procedure for performing FOTA updates successfully. These procedures
Involve:
•

Assisting customers with FOTA -related concerns if they have been unsuccessful in performing
the FOTA by themselves. (Possible vehicle or system concern.) *

•

Performing the FOTA update for customers who are not comfortable or need assistance with
performing it themselves but have requested the Retailer to install it*

* NOTE: If a customer is simply requesting help with how to perform FOTA, provide a copy of the
appropriate customer instructions for FOTA available on Subarunet: Service Operations & Technical>
Forms/Downloads page. See Appendix A later in this bulletin for more information.
It is VERY IMPORTANT to read and understand this information completely before proceeding.
CAUTION: VEHICLE SERVICING PERFORMED BY UNTRAINED PERSONS COULD
RESULT IN SERIOUS INJURY TO THOSE PERSONS OR TO OTHERS.
Subaru Service Bulletins are intended for use by professional technicians ONLY. They
are written to inform those technicians of conditions that may occur in some vehicles,
or to provide information that could assist in the proper servicing of the vehicle. Properly
trained technicians have the equipment, tools, safety instructions, and know-how to
do the job correctly and safely. If a condition is described, DO NOT assume that this
Service Bulletin applies to your vehicle, or that your vehicle will have that condition.

Subaru of America, Inc. is
ISO 14001 Compliant
ISO 14001 is the international standard for
excellence in Environmental Management
Systems. Please recycle or dispose of
automotive products in a manner that is friendly
to our environment and in accordance with all
local, state and federal laws and regulations.

Continued...
Bulletin Number: 15-326-25; Date: 06/17/25

Page 1 of 10

NOTES:
REMINDER: FOTA is available for HIGH (Navi) system with 11.6-inch display only.
•

The currently available FOTA firmware version is not the same version available to Retailers
for USB updating use. However, a system updated using FOTA can be further updated by using
the USB update procedure if additional updates are needed. For additional details clarifying
the scope of FOTA updates, review the applicable Owner’s Manual Supplement’s additional
information for the Center Information Display. The information is downloadable from:
https://www.subaru.com/ owners/index.html. See Appendix C below for moreinformation.

•

FOTA updates are for the system firmware ONLY. Map updates are a separate function which the
customer may update on their own by using either USB download or Map Over the AirUpdate
(MOTA). Go to: subaru-maps.com for more information.

SYMPTOMS ADDRESSED BY UPDATE:
This update addresses an issue in “Map Mode” on the digital instrument cluster, where the map may
fail to display and remain on “Loading Navigation” state.

SERVICE PROCEDURE / INFORMATION:
REMINDER: Customer satisfaction and retention starts with performing quality repairs. The
FOTA update process involves a remote downloading and installation the update firmware therefore,
time duration depends on signal strength and transfer rate performance. During installation, the
infotainment system’s functionality will be restricted.
SET-UP INSTRUCTIONS AND CAUTIONS:
•

Move the vehicle to an outside location where the engine can be safely started and kept idling
during the update process.

•

Never idle the vehicle in a closed space such as a garage, even if the garage door is kept open.

•

Once the vehicle is in a safe location, be sure the vehicle is in Park (CVT) or Neutral (MT) and
the parking brake is fully engaged.

•

Open one or more windows to ensure fresh air is available.

•

Stay with the vehicle until the update is completed.

•

We suggest adjusting the climate controls to your desired settings in case they become
unavailable during the update process.

•

Unplug any devices, chargers, cables or other USB drives from the vehicle’s USB and
powerports.
Continued...

Bulletin Number: 15-326-25; Date: 06/17/25

Page 2 of 10

VERY IMPORTANT: Before proceeding with the updating procedure, the currently installed
version ID MUST be confirmed (Firmware Version Check) by following the steps below:
1) After starting the engine and system boot-up completes, from the HOME screen, touch then
Settings button.

2) Press the General button. Use the down arrow to scroll to System Information then press to
display the System Information / Version information.

The examples below identify the head unit model and the last 6 digits 9xxx-xxx) signify the software
version number. Examples:
• FN1WWMxxx-xxx (High model software)
MY

Carline

Trim/Grade

Installed Software
Versions

Available Software
Version

High (Navigation)

094-481

144-470

WRX
25MY
FORESTER SHEV

If the software version number matches “Installed Software Versions” review the information
outlined below. If the software version is “Available Software Version” as the unit already has the
latest software version installed. Software version FH1WWM164-680 is post-countermeasure and
not eligible for the update. Proceed to the WARRANTY / CLAIM INFORMATION section of the
TSB and process a claim for Version Check Only.
Continued...
Bulletin Number: 15-326-25; Date: 06/17/25

Page 3 of 10

FOTA REPROGRAMMING OVERVIEW:
• SUBSCRIPTION STATUS - Confirm SUBARU STARLINK Safety Plus subscription
NOTE: FOTA update is possible only with valid SUBARU STARLINK Safety Plus subscription and
active DCM. If the status of subscription is unclear, contact STARLINK Customer Care at (855) 7532495 and find details of STARLINK agreement.
• SOFTWARE DOWNLOAD - When software update becomes available, the software is
automatically downloaded following IGN-ON operation without customer’s operation.
CAUTION: The process could be obstructed due to incorrect clock setting or poor DCM reception.
If the clock has wrong time, see Appendix B for how to set the correct time on the clock. If the DCM
has lost reception, move the vehicle to a better (4G phone signal) reception area.
Downloading automatically starts and finishes. While the DCM is downloading the new software,
all functions of Cockpit Control Unit remain available. The status of the downloading process can be
checked using Settings/General/Software update feature as shown below.

Normally downloading takes 10-20 minutes depending on reception condition. Even if is pressed in
the 3rd screen to return, downloading process continues.
In case of intermittent loss of reception by DCM (vehicle moving out of signal range), or Ignition
Switch being turned OFF, downloading is paused but the operation resumes as soon as the reception
is re-established or system is turned back on.
• INSTALLATION - The installation consists of two stages: installation and activation.
Notification screen is automatically displayed, after the background downloading has been
successfully completed. This screen is displayed only while the vehicle is not in motion. Select “Yes”
‘=> Start installation. Once “Yes” is pressed, installation continues even if the “X” button is pressed.

Continued...
Bulletin Number: 15-326-25; Date: 06/17/25

Page 4 of 10

Customers can skip installation by selecting up to two times. However, after
skipping two times the installation starts automatically as soon as the Ignition Switch is turned ON
without any notification. In that case the installation notification (3.a.i) is not displayed anymore. See
below for more information.

NOTES:
• If ignition Switch is turned OFF while 3.a.i screen is being displayed, the installation process is
terminated. In that case the screen 3.a.ii pops up automatically the next time the Ignition Switch is
turned on.
• If ignition Switch is turned OFF during 3.a.ii screen is being displayed, the installation process is
terminated. In that case installation process automatically resumes without showing 3.a.ii next time
the Ignition Switch is turned on.
• Activation: Wait until the installation is completed (Time required for installation: 15 minutes or
less). After the first installation process is coming to an end and the pop-up screen shown below
comes up, then press “OK.”

Switch the vehicle OFF, exit the vehicle, lock all doors including the rear gate (if equipped) and
move the key fob away from the vehicle at least 10 feet (3m) to enable affected systems to go to
sleep. WAIT AT LEAST 5 MINUTES prior to switching the vehicle ON to assure proper software
activation.
Bulletin Number: 15-326-25; Date: 06/17/25

Page 5 of 10

Pop-up screen shows up soon after the system completes to boot up. It confirms the software has been
installed.

NOTE: See Appendix D for troubleshooting tips if any errors are encountered.
WARRANTY / CLAIM INFORMATION:
WARRANTY / CLAIM INFORMATION: For vehicles within the Basic New Car Limited Warranty
period or covered by an active Subaru Added Security Gold plan, this repair may be submitted using
the following claim information:
Labor Description

Labor Operation #

Labor Time

Fail Code

DENSO CP1 VERSION CHECK ONLY

A031-178

.2H

ZTZ-48

IMPORTANT REMINDERS:
•

SOA strongly discourages the printing and/or local storage of service information as previously
released information and electronic publications may be updated at any time.

•

Always check for any open recalls or campaigns anytime a vehicle is in for servicing.

•

Always refer to STIS for the latest service information before performing any repairs.

Continued...
Bulletin Number: 15-326-25; Date: 06/17/25

Page 6 of 10

APPENDIX A
Links to Customer self-install instructions for FOTA Customer Instructions will be added to the
Subarunet Service Operations & Technical > Forms/Downloads page when they become available.
Once the links are available and to enhance customer satisfaction, consider providing customers
with a copy of the appropriate instructions for their specific system along with access to the retailer’s
secure customer Wi-Fi network. Doing so will enable customers to try performing the FOTA update
on their own while at the retailer.

REMINDER: Retailers performing these updates are to follow the Service Procedures outlined in
this bulletin ONLY. Always follow the applicable service procedures as outlined in this and other
Service Bulletins. The additional steps and requirements supplied in Service Bulletins support a
Subaru Technician’s proper diagnosis and repair of any customer concern.

Continued...
Bulletin Number: 15-326-25; Date: 06/17/25

Page 7 of 10

APPENDIX B

How to set the correct time on the clock
Software Update availability notification only works, if the clock has been set accurately. Check if the
time shown on the status bar is correct or not.

If the time is not correct, set the clock using procedure below.

a. Confirm GPS signal is received. Vehicle position on the map should match its location. If
necessary, drive the vehicle to assure good reception.
b. Check is Clock set to “Auto”: Setting”→”Clock”→”Time Setting” .
c. Once the Navi receives the GPS signal the clock is adjusted automatically.
d. If the GPS signal is not available, set the clock to “Manual Setting”.

a. a. Select “Setting”→”Clock”→”Time Setting” and check if the setting is “AUTO”. In case the
clock is not adjusted correctly, set the clock in “Manual” setting.

For more details, refer to the Owner`s Manual.
Continued...
Bulletin Number: 15-326-25; Date: 06/17/25

Page 8 of 10

APPENDIX C
The currently available FOTA software version is not the same version available to Retailers for USB
updating use. However, the system which has been updated via the FOTA can be further updated
using USB update when the software becomes available. Updating the firmware using a USB flash
drive by following the steps outlined in TSB 15-305-22R “Reprogramming File Availability for
Optimization of Gen 4.5 Denso CP1.5 Infotainment Systems”.

Continued...
Bulletin Number: 15-326-25; Date: 06/17/25

Page 9 of 10

APPENDIX D
TROUBLESHOOTING:
No.

Applicability

2-1

Case Scenario (Trouble)

Causes

Check Points

“In order to use the software update feature,
a SUBARU STARLINK subscription is needed.
Please visit MySubaru online for more
information.” is shown.

SUBARU STARLINK subscription is not confirmed

Please verify SUBARU
STARLINK subscription
status

An exception error due to
hardware malfunction

Downloading will resume
automatically 24hours later.
If same error message
again, please perform
diagnostic of CCU or update
CCU software via USB.

An exception error due to
hardware malfunction

Installation will resume
automatically 24hours later.
If same error message
again, please perform
diagnostic of CCU or update
CCU software via USB.

An exception error due to
hardware malfunction

Installation will resume
automatically 24hours later.
If same error message
again, please perform
diagnostic of CCU or update
CCU software via USB.

DCM has lost connection
to SUBARU server. After
downloading was completed, DCM needs to connect with SUBARU server,
before installing

Assure DCM has strong
reception and reliable
connection with the server,
then turn ignition OFF and
ON to repeat the test.

Step 2
(Downloaing)
“The software download failed.” popup is
shown while downloading.

2-2

“The software installation failed. An error
occurred during installation. Please contact
your retailer.” popup is shown while installing.

3-1

“The software installation failed. An error
occurred during installation. Please contact
your retailer.” popup is shown while installing.

3-2

Step 3
(Installation)

Selected , but next time IG
ON 3.a.i screen is not displayed.

3-3

Bulletin Number: 15-326-25; Date: 06/17/25

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