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 Lexus SC 400FACTORY OEM SERVICE PROCEDURE
Throttle Position (TP) Sensor
- To adjust main TP sensor on ES300, GS300 or SC300, disconnect vacuum hose from throttle opener. Apply vacuum to throttle opener to fully seat throttle. On all vehicles, disconnect TP sensor connector. Connect ohmmeter between terminals IDL (or IDL1 or IDL2) and E2 of TP sensor connector. See Fig 1.
- Insert appropriate size feeler gauge between throttle stop screw and lever. If continuity is as specified, TP sensor is adjusted. See THROTTLE POSITION SENSOR ADJUSTMENT table. If continuity is not as specified, loosen TP sensor mounting screws. Rotate TP sensor until continuity is as specified. Tighten mounting screws. Recheck adjustment.
THROTTLE POSITION SENSOR ADJUSTMENT
| Application & Throttle Plate Position (1)(2) | Continuity Between Terminals IDL & E2 | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| ES300 | |||||||||
| .014" (.35 mm) | Yes | ||||||||
| .028" (.70 mm) | No | ||||||||
| GS300 & LS400 | |||||||||
| Main TP Sensor | |||||||||
| .016" (.40 mm) | Yes | ||||||||
| (3) | No | ||||||||
| Sub-TP Sensor (With TRAC) | |||||||||
| .012" (.30 mm) | Yes | ||||||||
| .020" (.50 mm) | No | ||||||||
| SC300 | |||||||||
| Main TP Sensor | |||||||||
| .018" (.45 mm) | Yes | ||||||||
| .022" (.55 mm) | No | ||||||||
| Sub-TP Sensor (With TRAC) | |||||||||
| .014" (.35 mm) | Yes | ||||||||
| .020" (.50 mm) | No | ||||||||
| SC400 | |||||||||
| Main TP Sensor | |||||||||
| .016" (.40 mm) | Yes | ||||||||
| .026" (.65 mm) | No | ||||||||
| Sub-TP Sensor (With TRAC) | |||||||||
| .012" (.30 mm) | Yes | ||||||||
| .020" (.50 mm) | No | ||||||||
|
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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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