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 Forester BaseFACTORY OEM SERVICE PROCEDURE
Module I/O Signal
- Normal type
| Terminal No. | Item | Measuring condition | Standard |
|---|---|---|---|
| 1 (+B) ββ Chassis ground | Voltage | Always | 10 - 14 V |
| 2 (IG) ββ Chassis ground | Voltage | IG OFF β ON | 0 V β 8 V or more |
| 3 (GND) ββ Chassis ground | Resistance | Always | Less than 1 Ξ© |
| 4 (MFD SW+) ββ Chassis ground | Voltage | SW OFF β ON | 10 - 14 V β 0 V |
| 8 (U-ART com.) | - | Cannot be measured | - |
- High grade type
For the specification (electrical component), refer to the "Control Module I/O Signal" of the "MULTIFUNCTION DISPLAY (DIAGNOSTICS)" service information. Ref. to MULTI-FUNCTION DISPLAY (DIAGNOSTICS)>CONTROL MODULE I/O SIGNAL .
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:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.