Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2021 Subaru Outback BaseFACTORY OEM SERVICE PROCEDURE
Transmission Control Module (TCM): Removal
WARNING: This page is about a different variant/trim than selected.
CAUTION:
- When replacing the TCM, be sure to perform [Start count reading ECU to SSM] before operation and perform [Start count writing SSM to ECU] after operation. Ref. to AUTO START STOP (DIAGNOSTICS)>WORK SUPPORT>NOTE .
- When [Start count reading ECU to SSM] cannot be performed due to TCM malfunction, be sure to replace the starter and fuel pump relay at the same time.
Starter:
Ref. to STARTING/CHARGING SYSTEMS (H4DOTC)>STARTER .
Fuel pump relay:
Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>FUEL PUMP RELAY .
- Disconnect the ground terminal from battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
- Move the lock lever (B) in the arrow direction while pressing the lock button (A), and disconnect the connector.
- Remove the TCM.
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.