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
| ITEM | CONNECTOR NO. | TERMINAL NO. | INPUT/OUTPUT SIGNAL |
|---|---|---|---|
| MEASURED VALUE AND MEASURING CONDITIONS | |||
| Battery power supply | B281 | 6 | 9 - 16 V |
| 7 | |||
| i84 | 6 | ||
| Ignition power supply | B280 | 32 | 10 - 15 V when ignition switch is at ACC |
| B281 | 3 | 10 - 15 V when ignition switch is at ON or START | |
| TCM ("P" range) | i84 | 27 | Can not be measured because of digital communication |
| 35 | |||
| Stop light and brake switch | B280 | 10 | 9 - 16 V when the stop light & brake switch is ON 0 V when the stop light & brake switch is OFF |
| "P" range switch | B281 | 18 | 0 V when select lever is in "P" range 9 - 16 V when select lever is in other positions than "P" range |
| Solenoid unit signal | B281 | 5 | 9 - 16 V when shift lock is released 0 V when shift lock is operating |
| Key warning switch signal (Model without push button ignition switch) |
B280 | 4 | 9 - 16 V when key is inserted 0 V when key is removed |
| Key lock solenoid signal (Model without push button ignition switch) |
B281 | 4 | 7.5 - 16 V when the key is inserted with the select lever shifted in positions other than "P" range 0 V at other conditions than above |
| Ground | B280 | 1 | - |
| i84 | 1 |
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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