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 BaseFACTORY OEM SERVICE PROCEDURE
Diagnostic Method
Judge as NG if the criteria below are met.
Judgment value
JUDGMENT VALUE SPECIFICATION 1
| Malfunction Criteria | Threshold Value |
|---|---|
| (1) Throttle minimum stop position | ≥ 2.2 V |
JUDGMENT VALUE SPECIFICATION 2
| Malfunction Criteria | Threshold Value |
|---|---|
| (2) The learned value of accelerator pedal position in back-up RAM area 1 | not equal The learned value of accelerator pedal position in backup RAM area 2 |
JUDGMENT VALUE SPECIFICATION 3
| Malfunction Criteria | Threshold Value |
|---|---|
| (3) The sum of back-up RAM at the ECM shut down | not equal The sum of back-up RAM at the ECM powered-on |
JUDGMENT VALUE SPECIFICATION 4
| Malfunction Criteria | Threshold Value |
|---|---|
| (4) Communication between main CPU and sub CPU | Lost |
JUDGMENT VALUE SPECIFICATION 5
| Malfunction Criteria | Threshold Value |
|---|---|
| (5) The calculated data of throttle control by main CPU | not equal The calculated data of throttle control by sub CPU |
JUDGMENT VALUE SPECIFICATION 6
| Malfunction Criteria | Threshold Value |
|---|---|
| (6) The calculated data by main CPU | not equal The calculated data by FPU |
Time needed for diagnosis:
Judgment1, 2, 3, 4, 5: Less than 1 s
Judgment6: 200 ms
Malfunction indicator light illumination: Illuminates as soon as a malfunction occurs.
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.