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.
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HOMESERVICE MANUALSLEXUS1998SC 300REPAIR AND DIAGNOSISENGINE MECHANICALSTARTERON-VEHICLE TESTINGCIRCUIT TESTGS300
1998 Lexus SC 300
Circuit Test: GS300
1998 Lexus SC 300SECTION GS300
- Remove starter relay from underhood junction block. Check for battery voltage at junction block relay cavity terminal No. 5. Turn ignition to START. Check for battery voltage at junction block relay cavity terminal No. 1.
- Turn ignition off. Check for continuity between junction block relay cavity terminal No. 2 and ground. Check for continuity between junction block relay cavity terminal No. 5 and starter terminal No. 1 (Black/Red wire).
- Using DVOM, backprobe Natural ECM 28-pin connector E5 terminal 17 (Black wire). See Figure. Check for voltage with ignition in START position.
- Check for faulty starter relay, park/neutral position switch, or wiring harness. Repair as necessary.
RENDER: 1.0x
NO RELATED
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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.