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.
1998 Lexus SC 300FACTORY OEM SERVICE PROCEDURE
Ignition Coil Resistance
- Disconnect electrical connector and distributor wire from ignition coil. To measure primary resistance, measure resistance between terminals of ignition coil.
- To measure secondary resistance, measure resistance between positive wire terminal at ignition coil and coil secondary tower. See IGNITION COIL POSITIVE TERMINAL IDENTIFICATION table. If resistance is not as specified, replace ignition coil. See appropriate IGNITION COIL RESISTANCE table below.
IGNITION COIL POSITIVE TERMINAL IDENTIFICATION
| Application | Wire Color | |
|---|---|---|
| ES300 | Black/Red | |
| GS300 | Black | |
| LS400 | Black/Red | |
| SC300 | Black/White | |
| SC400 | ||
| Coil No. 1 | Black/Red | |
| Coil No. 2 | Black/White | |
IGNITION COIL RESISTANCE (ES300) - Ohms
| Application | Primary | Secondary | ||||
|---|---|---|---|---|---|---|
| Cold (1) | .70-.94 | 10,800-14,900 | ||||
| Hot (2) | .85-1.10 | 13,100-17,500 | ||||
|
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IGNITION COIL RESISTANCE (GS300) - Ohms
| Application | Primary | Secondary | ||||
|---|---|---|---|---|---|---|
| Cold (1) | .21-.33 | 6400-11,100 | ||||
| Hot (2) | .27-.39 | 8200-13,000 | ||||
|
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IGNITION COIL RESISTANCE (LS400 & SC400) - Ohms
| Application | Primary | Secondary | ||||
|---|---|---|---|---|---|---|
| Cold (1) | .36-.55 | 9000-15,400 | ||||
| Hot (2) | .45-.65 | 11,400-18,100 | ||||
|
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IGNITION COIL RESISTANCE (SC300) - Ohms
| Application | Primary | Secondary | ||
|---|---|---|---|---|
| Cold (1) | .21-.33 | 6400-11,100 | ||
| Hot (1) | .27-.39 | 8200-13,000 | ||
|
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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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