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.
Basic Diagnostic Procedure: Procedure
- PERFORM CUSTOMER INTERVIEW
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Ask the customer when and how the trouble occurred using the interview check list. Refer to AUTO START STOP (DIAGNOSTICS)>Check List for Interview .
Did you interview the customer?
Yes : Go to 2.
No : Perform the interview, and Go to 2.
- CHECK Auto Start Stop OFF INDICATOR
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Does the Auto Start Stop warning light (yellow) illuminate?
Yes : Go to 3.
No : Check the combination meter. Refer to ACTIVE TESTRefer to COMBINATION METER (DIAGNOSTICS)>Active Test .
- CHECK SUBARU SELECT MONITOR COMMUNICATION
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Check for communication with TCM.
NOTE: If the communication function of the Subaru Select Monitor cannot be executed properly, check the communication circuit. Refer to AUTO START STOP (DIAGNOSTICS)>Diagnostic Procedure for Subaru Select Monitor Communication .Is communication possible?
Yes : Go to 4.
No : Check the communication circuit. Refer to AUTO START STOP (DIAGNOSTICS)>Diagnostic Procedure for Subaru Select Monitor Communication .
- CHECK DTC
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Read the DTC of [Auto Start Stop] using the Subaru Select Monitor. Refer to AUTO START STOP (DIAGNOSTICS)>Diagnostic Trouble Code (DTC) .
Are any DTCs displayed?
Yes : Perform the diagnosis according to the DTC. After diagnosis, Go to 5.
No : Perform diagnosis according to the procedures in the diagnostics with phenomenon. Refer to AUTO START STOP (DIAGNOSTICS)>Diagnostics with Phenomenon .
- PERFORM DIAGNOSIS
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- Using the Subaru Select Monitor, perform the clear memory of [Auto Start Stop]. Refer to COMMON (DIAG)>CLEAR MEMORY .
- Execute the inspection mode. Refer to AUTO START STOP (DIAGNOSTICS)>Inspection Mode .
- Read the DTC of [Auto Start Stop] using the Subaru Select Monitor. Refer to AUTO START STOP (DIAGNOSTICS)>Diagnostic Trouble Code (DTC) .
Are any DTCs displayed?
Yes : Perform the diagnosis according to the DTC. Refer to AUTO START STOP (DIAGNOSTICS)>Diagnostic Trouble Code (DTC)>LIST .
No : Finish the diagnosis.
Use the Manual With the Right Hardware
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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.