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.
1992 Lexus LS 400FACTORY OEM SERVICE PROCEDURE
Throttle Position Sensor & Sub-Throttle Position Sensor
- Loosen TPS mounting screws. Unplug TPS and connect ohmmeter between throttle position sensor IDL and E2 terminals. See Fig 1, Fig 2 or Fig 3. Insert feeler gauge between throttle stop screw and lever. Feeler gauge should be .020" (.50 mm) on ES300, or .0157" (.40 mm) on LS400 and SC400. On SC300, feeler gauge should be .018" (.45 mm) on TPS and .014" (.35 mm) on sub-TPS.
- Rotate TPS clockwise until ohmmeter deflects. Tighten mounting screws. Using specified feeler gauge, recheck adjustment. See THROTTLE POSITION SENSOR ADJUSTMENT table. Remove ohmmeter and connect TPS.
THROTTLE POSITION SENSOR ADJUSTMENT
| Clearance Between Lever & Stop Screw | Ohmmeter Reading At Terminals IDL & E2 | |
|---|---|---|
| ES300 | ||
| .012" (.30 mm) | Continuity | |
| .028" (.70 mm) | No Continuity | |
| LS400 | ||
| .016" (.40 mm) | Continuity | |
| .034" (.85 mm) | No Continuity | |
| SC300 | ||
| .014" (.35 mm) | Continuity | |
| .020" (.50 mm) | No Continuity | |
| SC400 | ||
| .016" (.40 mm) | Continuity | |
| .026" (.65 mm) | No Continuity | |
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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