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Subaru Service and Technical Support Line Newsletter

SPECIAL EDITION
TROUBLESHOOTING AND IDENTIFYING USB TYPES WITH TECHLINE RECOMMENDATIONS

This information should be used as a guide to help identify cables found in a customer vehicle when
troubleshooting connectivity concerns regarding projection apps (Apple CarPlay or Android Auto). The
pictures below cover the USB type A end of the cord (not the phone side male plug). The different
colors of the USB plastic insert determine the level of power and data transfer the cable is capable of.
This does not determine the quality of the cable in use. A genuine cable from the manufacturer of the
device is always recommended. Typically, “the cable that came with the device when it was new in
the box” is the recommended cable to be using and testing with. This is because there is no standard
for the quality or quantity of copper inside the cable.
Before beginning this troubleshooting, if the cable
being used is dirty, frayed, kinked, or generally in
poor condition, the first diagnostic step after duplication of the concern should be a switch to an
OEM cable. The cable should not be wrapped or
tied around the shifter. This is a safety hazard and
induces movement into the system. A recommended
retailer strategy is to have a known good Apple cable
and USB 3.0 or higher cable kept by a shop foreman or
manager to be used solely in diagnostic comparison.
The first two levels of USB cables are USB 1.0
and USB 2.0. Techline has determined that the
colors are interchangeable depending on the
manufacturer of the cable, but USB 2.0 is typically
white. A cable that uses a black insert USB 1.0 should
only be used for low power charging, they are not
recommended for projection apps (Apple CarPlay or
Android Auto).
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CAUTION: VEHICLE SERVICING PERFORMED BY UNTRAINED PERSONS COULD
RESULT IN SERIOUS INJURY TO THOSE PERSONS OR TO OTHERS.

SUBARU OF AMERICA, INC. IS
ISO 14001 COMPLIANT

The Subaru TechTIPS newsletter is intended for use by professional Technicians ONLY. Articles 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 your vehicle has or will have that condition. Impreza,
Legacy, Justy, Loyale, Outback, Forester, Subaru SVX, WRX, WRX STI, Baja, Tribeca, BRZ, XV Crosstrek
and “Quality Driven” are Registered Trademarks.

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.

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What color are the USB Type A inserts being used on the vehicle?

A. Android, Apple, and Techline all recommend a cable no longer than 3ft (1m).
B. Not all cables can be mixed and matched for Android operating systems. For example, a
Google Pixel cable should only be used with a Pixel series phone. A Samsung cable should
only be used with a Samsung series phone. The cables are tailored to the phone and the
desired output. Consider interviewing the customer to determine the source of the cable and
what they have available to continue testing.
C. Apple recommends a USB 2.0 cable, all USB A-type Genuine Apple cables are USB 2.0
currently. Additional Apple cable recommendations can be found in the September 2021
TechTIP.

D. Techline does not recommend any adapters for USB A to USB C.

E. Techline, Android and Apple do not
recommend any cable with multiple tails,
typically labeled “3 in 1” charging cords.
These should not be used in projection apps
and may not charge the phone if the total
draw exceeds the rating on the USB hub.

At this time most Subaru model have the maximum power
output labeled on the USB port. TSB 15-226-18 can be
referenced on certain models.

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When troubleshooting a lag in loading (the amount of time the phone takes to detect the radio and enable projection) the first step is to inspect the cable being used. Referencing the chart above, notice the
rated speed difference between each level of USB cable. Trying to use a low-speed cable on a modern
phone will cause performance concerns and possible complete disconnection from the head unit. This
could result in multiple concerns, including but not limited to black screen, loss of connectivity, or loss
of function. Techline has observed this on all Infotainment platforms across all Subaru models. A key
detail that may indicate a cable issue is the head unit reverting to the home screen rather than a full
reboot back to the Starlink screen or vehicle information and basic functions of the Infotainment system
continue to work but all projection entertainment has stopped (FM, AM, menu selection operation still
function). Techline recommends any Android based phone produced after 2019 use at least a USB 3.0,
some high-performance phone models will require a USB 3.2 cable (light blue/teal) to work correctly.
Retailers may be presented with numerous projection app behavioral concerns, for example a music
streaming app not progressing through the songs properly, a lag in performance which may result in
a disconnection and projection app restart or general overall slowness until there is no response from
the head unit. Customers may report a screen display concern the longer they operate the vehicle, for
example while on a long road trip. Technicians should focus first on the cable being used to connect as well as the phone app being used rather than assuming the head unit is at fault.

Failure to Launch CarPlay or Android Auto Diagnostic Procedure
Use these procedures to troubleshoot projection app launching concerns. This flow chart should be
used in conjunction with TSB 15-220-18 for phone settings and compliance settings.
Example 1
Customer states that Apple CarPlay will not launch.
First step, clear all the open apps from any phone that is going to be used for testing.
Does the Technician iPhone detect and launch Apple CarPlay on the customer’s cable?
YES - Inspect the customer’s phone, the concern is not with the vehicle.
NO - Proceed to cable inspection.
Does the customer’s phone launch Apple CarPlay with the retailer’s OEM Apple cable?
YES - Test the Technician iPhone on the same vehicle, if both phones operate as designed,
use this document to inspect the cable and replace as needed.
NO - The customer’s iPhone and Technician iPhone do not launch Apple CarPlay with an
OEM cable. Proceed to supplemental USB hub testing.
As an alternative, test the customer’s phone and cable in a like vehicle with the same
brand and level Infotainment system.

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Example 2
Customer states Android Auto does not launch via USB cable.
First step, clear all the open apps from any phone that is going to be used for testing.
Does the Technician’s Android phone connect to Android Auto using the customer’s cable?
YES - Inspect the customer’s phone for OS and app software updates. Test the customer’s
phone and cable in a like vehicle with the same brand and level Infotainment system..
NO - Proceed to cable inspection.
Does the customer’s phone connect to Android Auto using the recommended USB 3.0 or higher
cable?
YES - Use this document to troubleshoot the customer cable and replace as needed.
NO - Proceed to the next step.
Does the technicians Android phone connect to the infotainment system using the same
USB cable?
YES - Stop, retest the customer’s phone and cable in a like vehicle with the same brand and
level Infotainment system.
NO - Proceed to supplemental USB troubleshooting.

Troubleshooting Intermittent Loss of Connection - Tethered
The first step is to inspect the cable and the position that the phone is stowed in. Reminder, this test
should be done with the customer’s phone and cable (a technician should consider collecting
photos of the customers setup). Techline finds most connection concerns to be at one of these two
places if there is no obvious physical damage to the cable.
The first inspection is the connection into the phone.
While inspecting the phone connection, here are some points of interest to keep in mind.
A. Is the connection loose?
B. Can it be wiggled and manipulated to create an instant loss of connection?
C. Where is the phone typically stowed when travelling in the vehicle?
D. Does an OEM cable have better fitment into the phone?
E. Does a USB-IF certified or USB 3.0 (or higher) improve the performance of the projection app?
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F. Does an OEM Apple cable improve the performance of the projection app?
- Does an MFI certified cable or OEM cable change the behavior over the long-term use? (a
couple of hours, days, or weeks).
G. Is there any foreign material preventing a good connection?
The second inspection is the USB cable connection to the vehicle.
A. Are their obstructions at the plug?
B. Visually inspect the plug and determine if anything can be changed about the position or situation?
C. Is anything else plugged into the USB or aux port? Remove them and retest.
- Inspect the back seat USB ports, and third row if applicable
D. Does a factory cable (OEM cable) have better fitment at the USB port?
E. Has the USB supplemental testing been performed? Continue to the next step.
Reminder, testing the Infotainment system and then making a diagnostic change to retest
the setup and/or system again is an essential step of troubleshooting. This step should not
be overlooked when trying to determine the source of the concern. Remember to make one
change to the setup and retest thoroughly before reverting or making additional changes.
Note: Bluetooth connections to a third device (Apple watch, Air Pods, NFC devices, for example) may
affect operation and should be turned off or out of range during diagnostics. Technicians should reference the August 2021 TechTIP for additional information.

Supplemental Troubleshooting for the USB Hub
How should a technician determine if the USB port is functioning correctly without disassembling the
vehicle? There are multiple ways of testing that can help determine if the USB port should be considered for replacement.
Strategy 1
Install the newest Infotainment software file (found in Forms/Downloads or from the SSM laptop) onto
a recently formatted, correctly sized USB drive. Plug the USB drive into the USB hub and follow the
normal steps for performing a head unit software update. Does the Infotainment system acknowledge an update is ready to proceed? If the answer is yes, the USB port is powered and connected
to the Infotainment system correctly. This would indicate the diagnostics should focus on the phone
cable, phone hardware, phone application being used or a head unit software concern that should
be reported using TSB 15-304-22. A Technician could seek authorization to perform a software update and verify that the data can be transferred and utilized, further proving the USB hub is working.

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Strategy 2
With the ignition in the “On” position, enter Dealership mode (6 button push) or Factory mode (2 button push). Navigate to the “Connection” screen.
On Gen 3 Harman equipped vehicles “USB 2” is used for the Telematics system (if the vehicle
is equipped). “USB 2” should be ignored for this test on Harman vehicles only. Both ports in
the USB hub will shift “USB 1” from “NG” to “OK”.
On Gen 4 Denso CP 1.0/CP 1.5 equipped vehicles, “USB 1” and “USB 2” are the respective USB
ports in the USB hub.
•

View the list of possible connections, they may take a minute to populate.

•

Observe “USB 1/2” at the start of this test, it should say “NG”. Plug the USB drive into the USB
hub, it should change to “OK”.

•

Remove the USB drive.

•

On Denso CP 1.0/1.5 vehicles it is necessary to back out of the “Connection” screen and go
back to it for the “USB” status to shift from “OK” back to “NG”.

•

Move the USB drive to the other USB hub port.

•

“USB 1/2” should say “OK” with the device plugged in again.

•

This is an acknowledgement of the device being plugged in and connecting. It is not recommended to perform this test with a cellular phone or similar device.

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If “USB 1” in the “Connection” menu always shows “NG” during the test, switch to a different USB
drive and test again. If this makes no change to the “OK” or “NG” status the next step should be
a visual inspection of the back of the head unit for a missing or damaged connector. Techline often
finds a craftmanship error and the USB hub connector is trapped near the floor pan area. If no missing or damaged connector are found, use STIS to refer to the “Body Electrical > Wiring system >
Audio System” to verify power and ground at the USB hub connector. Images of the Infotainment
connector layout can also be found in STIS, Diagnostics > Infotainment > Control Module I/O Signal.
Generally, there should be no empty plugs on the back of the head unit.

Strategy 3
A Technician or retailer can obtain a USB tester from a third-party source. This device has a small
display port that will track the available output voltage of the USB port. Does the USB hub have the
correct available 5 volts displayed by the USB testing device? If yes, the hub has power and ground
to it. Install the newest Infotainment software file (found in Forms/Downloads or from the SSM laptop) onto a recently formatted, correctly sized USB drive. Plug the USB drive into the USB hub and
follow the normal steps for performing a head unit software update. Does the Infotainment system
acknowledge an update is ready to proceed? If yes, the connection concern is not typically a vehicle
side concern, and the diagnostics should circle back to the customer phone and cable connection.
Some of these USB test devices can be switched to a pass-through mode where they will display the
amount of current draw when the customer cable and phone are connected. If the amperage draw
quickly tapers down to near zero, switch to an OEM or known good USB cable previously mentioned
for testing purposes. Does the condition remain the same? If so, switch to a similar vehicle and compare or switch to another cellular device. A damaged cable will typically cycle the power down as the
phone detects the concern with the cable.
Below is an example of a USB tester in use. The photo on the left indicates a normally operating
connection. The photo on the right shows a phone plugged in with the tester set to pass thru mode,
showing the charging Amps and Watts.

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