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Engine Controls - Removal, Overhaul & Installation: Overhaul Lexus LS III

Removal & Installation 5 illustrations ~2103 words

Disassembly & Reassembly (ES300)

Disconnect fuel pump connector. Pull off lower side of fuel pump from pump bracket. see scheme 30 Disconnect fuel hose from fuel pump. Remove fuel pump from fuel pump assembly bracket. Remove rubber cushion from fuel pump. Remove retaining clip and pull fuel pump screen from fuel pump. To reassemble, reverse disassembly procedure. Install NEW fuel pump assembly gasket and fuel pump screen retaining clip.

Disassembly & Reassembly (GS300, IS300, GS430, LS430 & RX300)

  1. Using 2 small screwdrivers, pry off No. 2 fuel suction support. see scheme 34 Ensure not to damage suction supports. Remove suction support rubber cushion. Disconnect fuel return jet tube from clamp of No. 2 suction support. Pull out fuel pressure regulator from in tank fuel filter and remove fuel pressure regulator and fuel return jet tube assembly. Remove "O" ring from fuel pressure regulator.
  2. Remove clip and remove fuel pump screen. Using 2 small screwdrivers, pry off No. 1 fuel suction support. Ensure not to damage suction support. Remove No. 2 fuel filter cushion. Disconnect fuel pump connector.
  3. Using a pulling motion, remove fuel filter and fuel pump assembly. see scheme 34 Remove No. 1 fuel filter cushion. Remove "O" ring from fuel port of fuel suction plate. Using a pulling motion, remove fuel pump from fuel filter.
  4. To reassemble, reverse disassembly procedure. Apply a light coat of gasoline to NEW "O" rings. Install NEW fuel pump assembly gasket and fuel pump screen retaining clip.

Disassembly & Reassembly (LX470)

  1. Disconnect lead wire from top of fuel pump. see scheme 36 Pull bottom of fuel pump from fuel pump mounting bracket. Disconnect fuel hose at top of fuel pump. Remove fuel pump with rubber cushion from fuel pump mounting bracket.
  2. Remove rubber cushion from bottom of fuel pump. Using small screwdriver, remove retaining clip that holds fuel filter on bottom of fuel pump. Remove fuel filter from fuel pump. To reassemble, reverse disassembly procedure using NEW retaining clip on fuel filter.

Disassembly (ES300 & RX300)

  1. If necessary to remove Throttle Position (TP) sensor, remove TP sensor retaining screws and TP sensor from throttle body. see scheme 42
  2. If necessary to remove Idle Air Control (IAC) valve, remove IAC valve retaining screws, bracket, IAC valve and gasket. If necessary to replace throttle bodies, remove protector, clip and plate washer. Disconnect accelerator link. Remove 6 throttle body retaining screws, No. 1 throttle body, No. 2 throttle body and 2 gaskets from No. 1 intake air control valve.

Reassembly (ES300 & RX300)

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.

Disassembly (GS300 & IS300)

  1. If necessary to remove Throttle Position (TP) sensor, remove retaining screws and TP sensor from throttle body. (Scheme 46)
  2. If necessary to remove throttle control motor, ensure Throttle Position (TP) sensor is removed from throttle body. Disconnect electrical connector for throttle control motor from wiring bracket. (Scheme 46) Remove retaining screws and cover to access throttle control motor. Remove retaining screws and throttle control motor from throttle body.
  3. If necessary to remove accelerator pedal position sensor, using small screwdriver, bend tabs on washer plate away from retaining screws for accelerator pedal position sensor. (Scheme 46) Remove retaining screws, washer plate and accelerator pedal position sensor from throttle body.

Scheme 46

Scheme 46
Scheme 46

Reassembly (GS300 & IS300)

  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 scheme 44 See «TORQUE SPECIFICATIONS»(ref-11568-S15357046272000111700000). Bend tabs on washer plate against retaining screws.
  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 scheme 45 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»(ref-11568-S15357046272000111700000).
  6. Install cover and retaining screws. Ensure grommet on throttle control motor is not pinched. Tighten cover retaining screws to specification. See «TORQUE SPECIFICATIONS»(ref-11568-S15357046272000111700000). 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 scheme 46 Rotate TP sensor counterclockwise to position No. 2 until it contacts throttle valve. see scheme 46 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 14.8 percent, as this is the center of the standard throttle valve opening of 14.0-15.6 percent. Tighten TP sensor retaining screws to specification. See «TORQUE SPECIFICATIONS»(ref-11568-S15357046272000111700000). 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 - 11 until correct throttle valve opening is obtained. Turn ignition off. Remove scan tool.

Disassembly (GS430 & LS430)

To remove TP sensor, remove 2 sensor retaining screws. Remove sensor. No other disassembly instructions are provided by manufacturer.

Reassembly (GS430 & LS430)

  1. To install TP sensor, ensure throttle valve opening on throttle body is 4 degrees or less. Install sensor on throttle body so it is at position No. 1 (15 degrees). (Scheme 47)
  2. Rotate TP sensor clockwise to position No. 2 until it contacts throttle valve. (Scheme 47) Install and tighten retaining screws to specification. See «TORQUE SPECIFICATIONS»(ref-11568-S15357046272000111700000).
  3. To check TP sensor operation after installation on throttle body, install electrical connector on TP 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 THROTTLE POS of the CURRENT DATA is 14.4-16.0 percent. If reading is not as specified, loosen and rotate TP sensor until reading is within middle of specified range. Retighten screws.

Scheme 47

Scheme 47
Scheme 47

Disassembly (LX470)

  1. If necessary to remove Throttle Position (TP) sensor, remove TP sensor retaining screws and TP sensor from throttle body. (Scheme 48)
  2. If necessary to remove throttle control motor, ensure TP sensor is removed from throttle body. Disconnect throttle control motor electrical connector from connector bracket. (Scheme 48)
  3. Remove throttle control motor cover-to-throttle body retaining screws from outside of throttle control motor cover. Remove throttle control motor cover with throttle control motor from throttle body.
  4. Remove throttle control motor-to-throttle control motor cover screws from inside of throttle control motor cover. Remove throttle control motor and wave washer from throttle control motor cover.
  5. If necessary to remove accelerator pedal position sensor, remove retaining screws and accelerator pedal position sensor from throttle body. (Scheme 48)

Scheme 48

Scheme 48
Scheme 48

Scheme 49

Scheme 49: Reassembly (LX470)
Scheme 49: Reassembly (LX470)

Scheme 50

Scheme 50
Scheme 50
  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). (Scheme 49)
  2. Rotate accelerator pedal position sensor clockwise to position No. 2 until it contacts throttle valve. (Scheme 49) Install and tighten retaining screws to specification. See «TORQUE SPECIFICATIONS»(ref-11568-S15357046272000111700000).
  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. 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. (Scheme 48)
  6. Install and tighten throttle control motor-to-throttle control motor cover screws to specification. See «TORQUE SPECIFICATIONS»(ref-11568-S15357046272000111700000). 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. (Scheme 48)
  7. Install washer on gear on throttle body. (Scheme 48) 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»(ref-11568-S15357046272000111700000). 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 5.5 degrees. Install TP sensor on throttle body so it is at position No. 1 (15 degrees). (Scheme 50) Rotate TP sensor counterclockwise to position No. 2 until it contacts throttle valve. Loosely install TP sensor retaining screws. 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»(ref-11568-S15357046272000111700000). 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 - 13 until correct throttle valve opening is obtained. Turn ignition off. Remove scan tool. Disconnect electrical connector at TP sensor.

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