LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2003 >> IS 300 Base, Standard >> Repair and Diagnosis (Single Page) >> External Pages >> Different car >> Section 16 (Engine Controls - System & Component Testing) >> Throttle Controls >> Throttle Body >> Throttle System Operation (GS430 & LS430)
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Throttle System Operation (GS430 & LS430)

WARNING: This page is about a different car, the 2002 Lexus SC 430, 2002 Lexus LS 430, 2002 Lexus IS 300, 2002 Lexus GS 430, and 2002 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. Remove engine cover. Ensure throttle linkage moves smoothly. Turn ignition on. Depress and release accelerator pedal several times and listen for smooth running sound from throttle control motor. If throttle control motor operates smoothly, go to step  3. If throttle control motor does not operate smoothly or cannot be heard at all, go to next step.
  2. Check throttle control motor operation. See THROTTLE CONTROL MOTOR (LS430 & GS430)  under MOTORS, RELAYS & SOLENOIDS. Replace as necessary. If throttle control motor operation is as specified, check for open or short circuit in wiring between throttle control motor and ECM. See WIRING DIAGRAMS article. Repair as necessary. If wiring is okay, go to next step.
  3. Check throttle position sensor operation. See THROTTLE POSITION (TP) SENSOR  under ENGINE SENSORS & SWITCHES. Replace as necessary. If throttle position sensor operation is as specified, check for open or short circuit in wiring between throttle position sensor and ECM. See WIRING DIAGRAMS article. Repair as necessary. If wiring is okay, go to next step.
  4. Check accelerator pedal position sensor operation. See ACCELERATOR PEDAL POSITION SENSOR  under ENGINE SENSORS & SWITCHES. Replace as necessary. If accelerator pedal position sensor operation is as specified, check for open or short circuit in wiring between accelerator pedal position sensor and ECM. See WIRING DIAGRAMS article. Repair as necessary. If wiring is okay, ECM may be defective. Check ECM. See PIN VOLTAGE CHARTS article. Repair as necessary.
scientia non olet · About LEMON Manuals