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.
1993 Subaru Justy BaseFACTORY OEM SERVICE PROCEDURE
Code 43: Throttle Switch
NOTE:
Refer to illustration for ECU connector and terminal identification. See Figure
. Power switch in integral to throttle switch.
- Turn ignition on. Backprobing ECU connector F120, measure voltage between ground and terminal No. 16 (Green/Red wire) of ECU. With throttle closed, voltage should be more than 8 volts. With throttle fully open, voltage should be less than one volt. If voltage is not as specified, go to next step. If voltage is as specified, check for poor ECU connector contact. Repair connector and/or wiring harness as necessary. If connector and wiring harness are okay, replace ECU.
- Turn ignition off. Disconnect throttle switch connector. Measure resistance between terminals No. 1 and 2 at throttle switch. See Figure . With throttle closed, resistance should be infinite. With throttle fully open, resistance should be less than one ohm. If resistance is as specified, go to next step. If resistance is not as specified, check throttle switch adjustment. See ADJUSTMENTS article. If throttle switch is adjusted properly, replace throttle switch.
- Disconnect ECU connectors. Measure resistance between ECU and throttle switch connectors and between ECU connector and ground. See the POWER SWITCH RESISTANCE SPECIFICATIONS table. If resistance is as specified, check for poor ECU connector contact. Repair connector and/or wiring harness as necessary. If connector and wiring harness are okay, replace ECU. If resistance is not as specified, repair connector and/or wiring harness as necessary.
POWER SWITCH RESISTANCE SPECIFICATIONS
| Measure Between Terminals | Ohms | ||||||
|---|---|---|---|---|---|---|---|
| No. 1 (1) & No. 2 (2) | Less Than One | ||||||
| No. 1 (1) & Ground | Less Than 10 | ||||||
| No. 16 (3) & Ground | Infinite | ||||||
| No. 16 (3) & No. 1 (2) | Less Than One | ||||||
| No. 10 (3) & Ground | Less Than 10 | ||||||
| No. 10 (3) & No. 2 (2) | Less Than One | ||||||
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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.