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.
2018 Subaru WRX STIFACTORY OEM SERVICE PROCEDURE
Drive Cycle P
| DTC | Item | Condition |
|---|---|---|
| P04F0 | EVAP SYSTEM HIGH PRESSURE PURGE LINE (CPC2) PERFORMANCE | Remaining fuel level 20 L or more |
Diagnostic procedure:
WARNING:
When performing drive cycle P on a public road, pay sufficient attention to the traffic condition and give the highest priority to safe driving.
- Drive according to the drive pattern described below.
- Park the vehicle on a safe place.NOTE: Driving method while vehicle is driven to a stop at safe place is not restricted.
- With the vehicle idling, read the temporary diagnostic code of DTC using Subaru Select Monitor or general scan tool.NOTE:
- For detailed operation procedures, refer to "Read Diagnostic Trouble Code (DTC)". Ref. to ENGINE (DIAGNOSTICS) (STI)>Read Diagnostic Trouble Code (DTC) .
- In the step 3), if the DTC is not displayed on the Subaru Select Monitor or general scan tool display screen, the trouble is resolved.
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.
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