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Throttle Body: Reassembly

To install TP sensor, ensure throttle valve is fully closed. Place TP sensor on throttle body with TP sensor turned clockwise 30-60 degrees against the fully closed throttle valve. Turn sensor clockwise until TP sensor mounting holes line up with throttle body mounting holes. Install and tighten TP sensor retaining screws. To install IAC valve, use a NEW IAC valve gasket. Position IAC valve on throttle body. Install and tighten IAC valve screws.



  1. To install accelerator pedal position sensor, install accelerator pedal position sensor, washer plate and retaining screws on throttle body. Tighten retaining screws to specification in sequence. See Figure. See TORQUE SPECIFICATIONS . Bend tabs on washer plate against retaining screws. See Figure.
  2. To check accelerator pedal position sensor operation after installation on throttle body, install electrical connector on accelerator pedal position sensor.
  3. Connect scan tool to Data Link Connector (DLC) No. 3 located under left side of instrument panel. Turn ignition on. DO NOT depress accelerator pedal after ignition is turned on. Using scan tool, check that ACCEL POS#1 (VPA) voltage of the CURRENT DATA is .3-.9 volt. This is the standard accelerator pedal position sensor voltage. Turn ignition off. Disconnect electrical connector for accelerator pedal position sensor.
  4. To install throttle control motor, ensure all gears on throttle control motor and throttle body are clean. Apply thin coat of grease on the entire surface of the gear teeth on the throttle body. Install throttle control motor on throttle body. Ensure holes on throttle control motor align with pins on throttle body.
  5. Rotate throttle control motor clockwise and install retaining screw "A". See Figure. Ensure throttle control motor is tight against the pins on throttle body. Install remaining retaining screws in throttle control motor. Tighten retaining screws to specification. See TORQUE SPECIFICATIONS .
  6. Install cover and retaining screws. Ensure grommet on throttle control motor is not pinched. Tighten cover retaining screws to specification. See TORQUE SPECIFICATIONS . Reinstall electrical connector for throttle control motor on wiring bracket.
  7. To install TP sensor, ensure throttle valve opening on throttle body is about 3.5 degrees. Install TP sensor on throttle body so it is at position No. 1 (30 degrees). See Figure. Rotate TP sensor counterclockwise to position No. 2 until it contacts throttle valve. See Figure. Install retaining screws.
  8. To check TP sensor adjustment, reinstall electrical connector on TP sensor. Connect scan tool to Data Link Connector (DLC) No. 3 under left side of instrument panel. Turn ignition on.
    NOTE: Ensure accelerator pedal is not depressed after turning ignition on when adjusting TP sensor.
  9. Use scan tool to read throttle valve opening which is displayed as a percentage. Throttle valve opening may be read by accessing THROTTLE POS under CURRENT DATA on scan tool.
  10. While reading throttle valve opening, rotate TP sensor counterclockwise (toward throttle control motor on throttle body) until throttle valve opening is 15.6 percent, as this is the center of the standard throttle valve opening of 14.4-16.8 percent. Tighten TP sensor retaining screws to specification. See TORQUE SPECIFICATIONS .
    NOTE: When TP sensor retaining screws are tightened, this may cause the throttle valve opening to change. Ensure throttle valve opening remains at 15.6 percent after TP sensor retaining screws are tightened. Readjust TP sensor if necessary.
  11. Using screwdriver, fully close throttle valve on throttle body. Use scan tool to read throttle valve opening by accessing THROTTLE POS under CURRENT DATA on scan tool. With throttle valve fully closed, throttle valve opening should be 10-14 percent.
  12. If throttle valve opening is not within specification with throttle valve fully closed, repeat steps 9)  through 11)  until correct throttle valve opening is obtained. Turn ignition off. Remove scan tool.


  1. To install accelerator pedal position sensor, ensure throttle valve opening on throttle body is about 4 degrees. Install accelerator pedal position sensor on throttle body so it is at position No. 1 (20 degrees). See Fig 1.
  2. Rotate accelerator pedal position sensor clockwise to position No. 2 until it contacts throttle valve. See Fig 1. Install and tighten retaining screws to specification. See TORQUE SPECIFICATIONS .
  3. To check accelerator pedal position sensor operation after installation on throttle body, install electrical connector on accelerator pedal position sensor. Connect scan tool to Data Link Connector (DLC) No. 3 under left side of instrument panel.
  4. Turn ignition on. DO NOT depress accelerator pedal after ignition is turned on. Using scan tool, check that ACCEL POS#1 (VPA) voltage of the CURRENT DATA is .35-.85 volt. This is the standard accelerator pedal position sensor voltage. Turn ignition off. Disconnect electrical connector for accelerator pedal position sensor.
    Fig 1: Installing Accelerator Pedal Position Sensor (GS400, LS400, LX470 & SC400)
    G98I10403Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    CAUTION: When installing throttle control motor in throttle control motor cover, ensure holes on throttle control motor align with pins on throttle control motor cover.
  5. To install throttle control motor, install wave washer in throttle control motor cover. Install throttle control motor in throttle control motor cover so that holes on throttle control motor align with pins on throttle control motor cover. Ensure grommet around wire for throttle control motor engages throttle control motor cover. See Figure.
  6. Install and tighten throttle control motor-to-throttle control motor cover screws to specification. See TORQUE SPECIFICATIONS . Ensure all gears on throttle control motor and throttle body are clean. Apply thin coat of grease on entire surface of gear teeth on the throttle body.
    CAUTION: Ensure washer is installed on gear on throttle body before installing throttle control motor. See Figure.
  7. Install washer on gear on throttle body. See Figure. Install throttle control motor cover with throttle control motor on throttle body. Ensure holes on throttle control motor cover align with pins on throttle body.
  8. Install and tighten throttle control motor cover-to-throttle body retaining screws to specification. See TORQUE SPECIFICATIONS . Reinstall throttle control motor electrical connector on connector bracket. Reinstall and adjust TP sensor.
  9. To install TP sensor, ensure throttle valve opening on throttle body is about 4 degrees. Install TP sensor on throttle body so it is at position No. 1 (15 degrees). See Fig 2. Rotate TP sensor counterclockwise to position No. 2 until it contacts throttle valve. See Fig 2. Loosely install TP sensor retaining screws.
    Fig 2: Installing TP Sensor (GS400, LS400, LX470 & SC400)
    G98J11915Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    NOTE: Ensure electrical connector is not installed on accelerator pedal position sensor when checking TP sensor adjustment.
  10. To check TP sensor adjustment after installation on throttle body, install electrical connector on TP sensor. Ensure electrical connector is NOT installed on accelerator pedal position sensor. Connect scan tool to data link connector No. 3 under left side of instrument panel. Turn ignition on.
    NOTE: Ensure accelerator pedal is not depressed after turning ignition on when adjusting TP sensor.
  11. Use scan tool to read throttle valve opening which is displayed as a percentage. Throttle valve opening may be read by accessing THROTTLE POS under CURRENT DATA on scan tool.
  12. While reading throttle valve opening, rotate TP sensor clockwise and counterclockwise until throttle valve opening is 15.2 percent, as this is the center of the standard throttle valve opening of 14.4-16.0 percent. Tighten TP sensor retaining screws to specification. See TORQUE SPECIFICATIONS . When TP sensor retaining screws are tightened, this may cause the throttle valve opening to change. Ensure throttle valve opening remains at 15.2 percent after TP sensor retaining screws are tightened. Readjust TP sensor if necessary.
  13. Ensure throttle valve on throttle body is fully closed. Use scan tool to read throttle valve opening by accessing THROTTLE POS under CURRENT DATA on scan tool. With throttle valve fully closed, throttle valve opening should be 10-14 percent.
  14. If throttle valve opening is not within specification with throttle valve fully closed, repeat steps 11)  through 13)  until correct throttle valve opening is obtained. Turn ignition off. Remove scan tool. Disconnect electrical connector at TP sensor.
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