15-300-22R Service Bulletin/Repair Instructions

ATTENTION:

GENERAL MANAGER
q
PARTS MANAGER
q
CLAIMS PERSONNEL
q
IMPORTANT - All

Service Personnel

Should Read and

Initial in the boxes

provided, right.
SERVICE MANAGER
q
© 2022 Subaru of America, Inc. All rights reserved.
SERVICE BULLETIN

APPLICABILITY:
All Gen2 and Gen3 Telematics Equipped Models
NUMBER: 15-300-22R
SUBJECT: STARLINK® Telematics Remote Engine Start

		 Only runs 15 seconds after successful engine

		start
DATE:
08/29/22
REVISED:
01/12/26
INTRODUCTION:

This Service Information Bulletin provides the diagnostic procedure for the STARLINK® Remote

Engine Start (RES). In some cases, after successfully initiating STARLINK® Telematics Remote

Engine Start, the vehicle will run for only 15 seconds and then turn off. The information contained

in this bulletin is only to be used when diagnosing this described condition. The information in this

bulletin DOES NOT apply to the Subaru Long Range Remote Start Accessory.

Applicability

Model
MY 2019
MY 2020
MY 2021
MY 2022
MY 2023
MY 2024
MY 2025
MY 2026
Ascent
Gen 2
Gen 2
Gen 2
Gen 2
Gen 3
Gen 3
Gen 3+
Gen 3 +
Crosstrek
Gen 2
Gen 2
Gen 2
Gen 2
Gen 2
Gen 3
Gen 3 +
Gen 3 +
Crosstrek Hybrid
Gen 2
Gen 2
Gen 2
Gen 2
Gen 2
Gen 2
n/a
Gen 3 +
Forester
Gen 2
Gen 2
Gen 2
Gen 2+
Gen 2+
Gen 2+
Gen 3
Gen 3
Forester SHEV
n/a
n/a
n/a
n/a
n/a
n/a
Gen 3
Gen 3
Forester Wilderness
n/a
n/a
n/a
Gen 2+
Gen 2+
Gen 2+
Gen 2 +
Gen 3
Impreza
Gen 2
Gen 2
Gen 2
Gen 2
Gen 2
Gen 3
Gen 3+
Gen 3+
Legacy
Gen 1
Gen 2
Gen 2
Gen 2
Gen 3
Gen 3
Gen 3+
n/a
Outback
Gen 1
Gen2
Gen 2
Gen 2
Gen 3
Gen 3
Gen 3+
Gen 4
WRX
Gen 1
Gen 1
Gen 1
Gen 2+
Gen 2+
Gen 3
Gen 3+
Gen 3+
BRZ
n/a
n/a
n/a
Gen 2+
Gen 2+
Gen 2+
Gen 2+
Gen 2+
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: 15-300-22R; Revised: 01/12/25
Page 1 of 9
SERVICE PROCEDURE / INFORMATION:

REMINDER: Customer satisfaction and retention starts with performing quality repairs.

The use of this document relies heavily on electrical system information, wiring schematics,

diagrams, components connector locations and testing methods that are found in the Body &

Electrical / Wiring System Sections of the Subaru Technical Information System (STIS). A

Technician should be proficient with their use of STIS and possess advanced electrical diagnosis

skills before attempting to use this document. Due to the complexity of the test procedure and the

electrical systems involved, it is essential that the Technician practices strict adherence to the process

and take particular care not to introduce a secondary fault(s) into these systems. Any improper testing

methodology could lead to unnecessary component damage/replacement or harness damage. When

engaging Techline with questions, be prepared with DVOM measurements or oscilloscope patterns

for every step of the diagnostic procedure. Failure to provide accurate measurements and review of

your testing methodology will significantly impede Techline’s ability to provide efficient support.

IMPORTANT: This procedure looks for incorrect or induced voltages to the circuit by outside

influence on the Data Control Module (DCM), Keyless Access Control Module (KACM), Engine

Control Module (ECM), and Body Integrated Unit (BIU) power supply circuits. Taking extra time

inspecting the vehicle for aftermarket accessories installed is critical, so that test results are not

skewed. Accessories such as backup cellphone batteries plugged into USB ports or battery jump

packs plugged into 12V charging ports can back feed voltage and influence vehicle operation,

including the test results.

The retailer should secure the use of the customer’s MySubaru account during the diagnosis for this

concern. There will be significant STARLINK® Remote Engine Start use during diagnosis and repair.

Relying only on the customer to perform RES is inefficient and unreliable for this testing.

CRITICAL: Use of this trouble tree assumes that the telematics system is clear of any current

DTCs and passes operational checks other than expected remote engine start operation. If there are

any current telematics DTCs or observed unexpected behavior, consult with Techline or your Field

Service Engineer prior to use of this trouble tree.
Continued...

Bulletin Number: 15-300-22R; Revised: 01/12/25
Page 2 of 9
1. PRELIMINARY CHECKS

1. Confirm there are no aftermarket accessories installed in the vehicle.

2. Make sure nothing is plugged into any of the USB ports.

3. Make sure a cell phone is not sitting on the charging pad if equipped.

4. Pull Fuse No. 4 in passenger side fuse box.

5. With Push Button off and Engine Off check both sides of Fuse No. 4 in the

passenger side fuse panel for voltage by applying the negative test lead to ground

and the positive lead to both sides of the fuse.

IS VOLTAGE AT FUSE NO. 4 GREATER THAN 1 VOLT?
YES: Go to Step 2: ACCESSORY RELAY NO. 1.
NO: 0 V found at both sides of Fuse No. 4. Go to Step 6: KACM A19
2. ACCESSORY RELAY NO. 1

1. Remove accessory relay 1 from passenger side fuse panel.

2. With Push Button off and Engine Off check both sides of Fuse No. 4 in the
passengerside fuse panel for voltage by applying the negative test lead to ground

and the positivelead to both sides of the fuse.

IS VOLTAGE AT FUSE NO. 4 GREATER THAN 1 VOLT?
YES: Go to Step 3: ACCESSORY FUSE.
NO: Go to Step 2a: ACCESSORY RELAY NO. 1 PART 2.
Continued...

Bulletin Number: 15-300-22R; Revised: 01/12/25
Page 3 of 9
2a. ACCESSORY RELAY NO. 1, PART 2

1. Swap accessory relay 1 with accessory relay 2.

2. With Push Button off and Engine Off check both sides of Fuse No. 4 in the
passengerside fuse panel for voltage by applying the negative test lead to ground

and the positivelead to both sides of the fuse.
IS VOLTAGE AT FUSE NO. 4 GREATER THAN 1 VOLT?
YES: Go to Step 4: KACM
NO: Replace accessory relay 1 that should now be installed in accessory relay 2

position. Go to Step 8: REINSTALL AND RETEST.
3. ACCESSORY FUSE

1. Remove accessory fuse feeding terminal A20 of the DCM from the driver’s side fuse

panel.
Ascent / Crosstrek / Forster / Impreza = Fuse No. 54 (ACC)

Legacy / Outback / WRX = Fuse No. 51 (ACC)
2. With Push Button off and Engine Off check both sides of Fuse No. 4 in the
passengerside fuse panel for voltage by applying the negative test lead to ground

and the positivelead to both sides of the fuse.

IS VOLTAGE AT FUSE NO. 4 GREATER THAN 1 VOLT?
YES: Find short to power or unexpected power supply on circuit between Fuse

No. 4 of passenger fuse panel and Accessory Fuse feeding terminal A20 of DCM

in drivers fuse panel.
NO: Reinstall Accessory Fuse. Determine components fed by Accessory Fuse in

drivers fuse box and disconnect them one at a time retesting at Fuse No. 4 after

each component is removed to determine if it is the source of the unexpected

voltage.
After repair of above findings (either short to power at harness or component

supplying unexpected voltage) go to Step 8: REINSTALL AND RETEST.
Continued...

Bulletin Number: 15-300-22R; Revised: 01/12/25
Page 4 of 9
4. KACM

1. Disconnect KACM.

2. With Push Button off and Engine Off check both sides of Fuse No. 4 in the passenger
side fuse panel for voltage by applying the negative test lead to ground and the positive

lead to both sides of the fuse.
IS VOLTAGE AT FUSE NO. 4 GREATER THAN 1 VOLT?
YES: Go to Step 5: KACM ISOLATION
NO: Replace KACM. Go to Step 8: REINSTALL AND RETEST.
5. KACM ISOLATION

1. Remove Accessory relay 1 and accessory relay 2 from the passenger fuse panel.

2. Using DVOM with red lead connected to terminal A16 of KACM connector and black

lead connected to the under-hood battery negative terminal measure resistance.
IS RESISTANCE AT TERMINAL A16 LESS THAN 1 MEGA OHM?
YES: Short to ground indicated on circuit. Replace harness.
NO: DVOM indicates OL. Replace KACM. Go to Step 8: REINSTALL AND RETEST.
NOTE: The prerequisite for moving to Step 6: KACM A19 is with Pushbutton off, Engine Off there

is no voltage at Fuse No. 4 of the passenger side fuse panel. If voltage is still present at Fuse No.

4 start testing over at Step 1: PRELIMINARY CHECKS or contact Techline for assistance before

proceeding.
Continued...

Bulletin Number: 15-300-22R; Revised: 01/12/25
Page 5 of 9
6. KACM A19

1. Measure the voltage change at the A19 terminal (back probing) of the KACM when the remote engine starting operation is performed.
NOTE: While back probing the terminal A19, the ignition must be off, car in park,

doors and hood closed and the key fob away from the vehicle. On some models the

windows must also be up. Then perform the remote start request from the Customer

Web Portal or the MySubaru App. Deviating away from expected RES car side status

will produce the incorrect test results.

WHAT IS THE VOLTAGE AT TERMINAL A19 OF THE KACM?

Voltage at A19 is always 0 V: Go To Step 6a: KACM A19 ALWAYS 0 VOLTS

Voltage at A19 is always 12 V: Go To Step 6b: KACM A19 ALWAYS 12 VOLTS

Voltage at A19 varies 12V – 0V – 12V: Go To Step 6c: KACM A19 VARYING VOLTAGE.
6a. KACM A19 ALWAYS 0 VOLTS

1. Performing step 6.1 the DVOM always read 0 volts at the A19 terminal (back probing) of

the KACM when the remote engine starting operation is performed.
IS THE VOLTAGE AT TERMINAL A19 OF KACM ALWAYS 0 VOLTS?

Perform inspection of harness for abnormalities such as open circuit or excessive

resistance. Was harness abnormality found?

YES: Replace Harness

NO: Replace KACM. Go to Step 8: REINSTALL AND RETEST.
6b. KACM A19 ALWAYS 12 VOLTS

1. . Performing step 6.1 the DVOM always read 12 volts at the A19 terminal (back probing) of

the KACM when the remote engine starting operation is performed.
IS THE VOLTAGE AT TERMINAL A19 OF KACM ALWAYS 12 VOLTS?

Perform inspection of harness for abnormalities such as short to power. Was harness abnormality found?

YES: Replace Harness

NO: Replace ECM. Go to Step 8: REINSTALL AND RETEST.
Continued...

Bulletin Number: 15-300-22R; Revised: 01/12/25
Page 6 of 9
6c. KACM A19 VARYING VOLTAGE.

1. Performing step 6.1 the DVOM measurement varied 12V – 0V – 12 V at the A19 terminal (back probing) of the KACM when the remote engine starting operation is performed.

IS THE VOLTAGE AT TERMINAL A19 OF KACM VARYING 12V TO 0v TO 12V DURING RES OPERATION?

YES: Go to Step 7: KACM A16

NO: Replace KACM. Go to Step 8: REINSTALL AND RETEST.
7. KACM A16

1. Measure voltage at terminal A16 of KACM during remote engine start operation with an

oscilloscope.
NOTE: Refer to STIS document MSA5T2101T Subaru Diagnostic Systems (SDS)

(June 2021) pages 4-1 through 4-28 for oscilloscope operation.

WHAT IS THE VOLTAGE AT TERMINAL A16 OF THE KACM?

Voltage at A16 is always 0 V: Go To Step 7a: KACM A19 ALWAYS 0 VOLTS.

Voltage at A16 is always 12 V: Go To Step 7b: KACM A19 ALWAYS 12 VOLTS.

Voltage at A16 varies 12V – 0V – 12V: Go To Step 7c: KACM A19 VARYING

VOLTAGE.
7a. KACM A16 ALWAYS 0 VOLTS.

1. Performing step 7.1 the oscilloscope always read 0 volts at terminal A16 of KACM during remote engine start operation.
NOTE: Refer to STIS document MSA5T2101T Subaru Diagnostic Systems (SDS)

(June 2021) pages 4-1 through 4-28 for oscilloscope operation.

IS THE VOLTAGE AT TERMINAL A16 OF KACM ALWAYS 0 VOLTS?

Perform inspection of harness for abnormalities such as open circuit or

excessive resistance. Was harness abnormality found?

YES: Replace Harness

NO: Replace KACM. Go to Step 8: REINSTALL AND RETEST.
Continued...

Bulletin Number: 15-300-22R; Revised: 01/12/25
Page 7 of 9
7b. KACM A16 ALWAYS 12 VOLTS.

1. . Performing step 7.1 the oscilloscope always read 12 volts at terminal A16 of KACM

during remote engine start operation.
NOTE: Refer to STIS document MSA5T2101T Subaru Diagnostic Systems (SDS)

(June 2021) pages 4-1 through 4-28 for oscilloscope operation.

IS THE VOLTAGE AT TERMINAL A16 OF KACM ALWAYS 12 VOLTS?

Perform inspection of harness for abnormalities such as short to power. Was

harness abnormality found?

YES: Replace Harness

NO: Replace KACM. Go to Step 8: REINSTALL AND RETEST.
7c. KACM A16 VARYING VOLTAGE.

1. Performing step 7.1 the oscilloscope read 12V – 0V – 12V at terminal A16 of KACM

during remote engine start operation with an oscilloscope.
NOTE: Refer to STIS document MSA5T2101T Subaru Diagnostic Systems (SDS)

(June 2021) pages 4-1 through 4-28 for oscilloscope operation.
IS THE VOLTAGE AT TERMINAL A16 OF KACM VARYING 12V TO 0v TO 12V DURING RES OPERATION?

Perform inspection of terminal A16 of KACM for abnormalities such as intermittent open, excessive resistance or short to ground. Was harness abnormality

found?

YES: Replace Harness

NO: Replace BIU. Go to Step 8: REINSTALL AND RETEST.
Continued...

Bulletin Number: 15-300-22R; Revised: 01/12/25
Page 8 of 9
8. REINSTALL and RETEST.

1. Reinstall all components removed for testing.

2. Retest operation of Remote Engine Start for expected behavior.
DOES RES EXHIBIT BEHAVIOR OF RUNNING 15 SECONDS THEN SHUTTING OFF?
YES: Go to Step 1: PRELIMINARY CHECKS.
NO: If RES starts as expected and runs for the selected period vehicle is repaired

and no further action is necessary.
WARRANTY / CLAIM INFORMATION:

There have been no changes made to the Warranty Labor Time Guide regarding these procedures.
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.
Bulletin Number: 15-300-22R; Revised: 01/12/25
Page 9 of 9

Bestseller No. 1

ANCEL AD310 Classic Enhanced Universal OBD II Scanner Car Engine Fault Code Reader CAN Diagnostic Scan Tool, Read and Clear Error Codes for 1996 or Newer OBD2 Protocol Vehicle (Black)

CEL Doctor: The ANCEL AD310 is one of the best-selling OBD II scanners on the market and is recommended by Scotty Kilmer, a YouTuber and auto mechanic. It can easily determine the cause of the check engine light coming on. After repairing the vehicle's problems, it can quickly read and clear diagnostic trouble codes of emission system, read live data & hard memory data, view freeze frame, I/M monitor readiness and collect vehicle information.
Sturdy and Compact: Equipped with a 2.5 foot cable made of very thick, flexible insulation. It is important to have a sturdy scanner as it can easily fall to the ground when working in a car. The AD310 OBD2 scanner is a well-constructed mechanic tool with a sleek design. It weighs 12 ounces and measures 8.9 x 6.9 x 1.4 inches. Thanks to its compact design and light weight, transporting the device is not a problem. The buttons are clearly labelled and the screen is large and displays results clearly.
Accurate Fast and Easy to Use: The AD310 scanner can help you or your mechanic understand if your car is in good condition, provides exceptionally accurate and fast results, reads and clears engine trouble emission codes in seconds after you fixed the problem. This device will let you know immediately and fix the problem right away without any car knowledge. No need for batteries or a charger, get power directly from the OBDII Data Link Connector in your vehicle.
OBDII Protocols and Car Compatibility: Many cheap scan tools do not really support all OBD2 protocols. AD310 scanner as it can support all OBDII protocols such as KWP2000, J1850 VPW, ISO9141, J1850 PWM and CAN. This device also has extensive vehicle compatibility with 1996 US-based, 2000 EU-based and Asian cars, light trucks, SUVs, as well as newer OBD2 and CAN vehicles both domestic and foreign. Pls confirm with our customer service whether it is compatible with your vehicle before purchasing.
Home Necessity and Worthy to Own: This is an excellent code reader to travel or home with as it weighs less and it is compact in design. You can easily slide it in your backpack as you head to the garage, or put it on the dashboard, this will be a great fit for you. The AD310 is not only portable, but also accurate and fast in performance. Moreover, it covers various car brands and is suitable for people who just need a code reader to check their car.

Bestseller No. 2

MOTOPOWER MP69033 Car OBD2 Scanner Code Reader Engine Fault Scanner CAN Diagnostic Scan Tool for All OBD II Protocol Cars Since 1996, Yellow

Multi-Functions - Practical Multi-Functions OBD2 code reader features built-in OBD2 DTC lookup library, which help you to determine the cause of the engine light, read code, erase code, view freeze frame, I/M ready, vehicle information, data flow, real-time curve, get vehicle speed information, calculate load value, engine coolant temperature, get engine speed.
Wide Capability - Supports 9 protocols compatible with most 1996 US-Based, 2000 EU-Based and Asian cars, and newer OBD II & CAN domestic or import vehicles. Supports 6 languages - English,German, Dutch, Spanish, French, Italian.
2.8" LCD Display - Designed with a clear display 2.8" Large LCD screen - white backlight and contrast adjustment. No need any battery or charger, OBD reader gets the power directly from your vehicle through the OBDII Data Link Connector.
Compact Design - Car diagnostic scanner is equipped with a 2.5 feet long cable and made of a very thick flexible insulator.There are 6 buttons on OBD2 Scanner:scroll up/down,enter/exit and buttons that quick query VIN vehicle number& the DTC fault code.
ABS / Airbag codes NOT Supported - It is able to read and clear check engine information which is part of OBDII system, but it cannot work with non-OBDII systems, including ABS / Airbag / Oil Service Light, etc.

Bestseller No. 3

FOXWELL NT301 OBD2 Scanner Live Data Professional Mechanic OBDII Diagnostic Code Reader Tool for Check Engine Light

【Your Personal CEL Doctor – Read & Clear Engine Codes】The NT301 OBD2 scanner lets you read diagnostic trouble codes (DTCs), check em-issions readiness, turn off your Check Engine Light (CEL) or MIL, reset monitors, and view live data streams. It retrieves your vehicle's VIN instantly. Like all standard OBD2 scanners, it clears codes only after repairs are completed—if the issue persists, the code will return. Designed for DIYers who want to understand what’s really going on under the hood.
【Easy Code Reading – Just Plug & Play】Simply plug into the OBD2 port, turn the ignition to “ON” (engine off), and select the correct menu: Select OBDII-> Wait for seconds-> Select Read codes. For accurate results, ensure your vehicle is compatible and the OBD2 port is free from damage or wiring issues. No batteries needed— powered directly by your car.
【Live Data Graphing & Accuracy for Most OBD2 Vehicles】View and log live sensor data in graph form—monitor oxygen sensors, fuel trims, coolant temp, RPM, and more. Spot trends and suspicious values in real time. Compatible with most 1996+ gasoline cars, light trucks, and SUVs sold in the U.S., as well as many 2000+ European and Asian models. Also works on 12V diesel vehicles equipped with OBD2.
【S-mog Check Helper – Know Your Readiness Status at a Glance】With dedicated I/M readiness hotkeys and a simple Red-Yellow-Green LED indicator, you’ll instantly know if your vehicle is ready for em-issions testing. Built-in speaker provides audio feedback. No guesswork—just confidence before you head to the test center.
【A Must-Have Tool for Every Home Mechanic】Compact, rugged, and ready to use right out of the box. The 2.8” color screen is easy to read, even in daylight. No charging or setup required—just plug into the 16-pin DLC and start diagnosing. Recommended by professional mechanics on YouTube and trusted by DIYers worldwide.

Last update on 2026-03-25 / Affiliate links / Images from Amazon Product Advertising API

This product presentation was made with AAWP plugin.

Buffer Copy Email Facebook Flipboard Hacker News LinkedIn Messenger Mix Pinterest Print Reddit SMS Telegram Tumblr X VK WhatsApp Line Xing Threads