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 BaseFACTORY OEM SERVICE PROCEDURE
Electrical Specification
| Description | Connector No. | Terminal No. | Signal (V) | Note | ||
|---|---|---|---|---|---|---|
| Ignition SW ON (Engine OFF) |
Engine ON (Idling) |
|||||
| Brake booster pressure sensor | Signal | E158 | 13 | 1 - 3.8 | 1 - 3.8 | - |
| Power supply | B134 | 18 | 5 | 5 | - | |
| Ground | B134 | 19 | 0 | 0 | - | |
| Self-shutoff control | B134 | 38 | 0 | 0 | - | |
| Brake vacuum pump | Relay drive | E158 | 37 | 10 - 13 (When pump is OFF) |
12 - 14 (When pump is ON) |
- |
| 0 (When pump is ON) | 0 (When pump is ON) | |||||
| Electric load | E158 | 1 | 0 (When pump is OFF) | 0 (When pump is OFF) | - | |
| 10 - 13 (When pump is ON) |
12 - 14 (When pump is ON) |
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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.
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