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.
1990 Lexus LS 400FACTORY OEM SERVICE PROCEDURE
Throttle Position Sensor
- Loosen TPS mounting screws. Unplug TPS and connect ohmmeter between throttle position sensor "IDL" and "E2" terminals. See Fig 1. Insert a .020" (.50 mm) on ES250 or .0157" (.40 mm) on LS400 feeler gauge between throttle stop screw and lever.
- 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" |
|---|---|
| .0157" (.40 mm) | Continuity |
| .0335" (.85 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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