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 WRX STIFACTORY OEM SERVICE PROCEDURE
Diagnostic Method
Judge as NG when the following conditions are established.
Diagnosis 1
JUDGMENT VALUE SPECIFICATION - DIAGNOSIS 1
| Malfunction Criteria | Threshold Value |
|---|---|
| Time needed for storing data in EEPROM | ≥ 48 ms |
Diagnosis 2
JUDGMENT VALUE SPECIFICATION - DIAGNOSIS 2
| Malfunction Criteria | Threshold Value |
|---|---|
| EEPROM writing | Error |
Time needed for diagnosis:
- Diagnosis 1: 48 ms
- Diagnosis 2: 2 times
Malfunction indicator light illumination: Illuminates as soon as a malfunction occurs.
Factory Service Tools
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.