Engine Controls - On-Vehicle Adjustments: Other Lexus LS III

ENGINE MECHANICAL

Before performing any on-vehicle adjustments to fuel or ignition systems, ensure engine mechanical condition is okay.

VALVE CLEARANCE

Note. Check and adjust valves with engine cold.

ES300 & RX300

Note. On RX300 models, start at step 1 . On ES300 models, start at step 2 .

Scheme 10

Scheme 11

Scheme 12

Scheme 13

1. On RX300 models, remove outer cowl top panel. (Scheme 10) Remove windshield wiper arm nuts and windshield wiper arms assemblies. Place protective tape along bottom of windshield to protect windshield. Remove cowl top seal. Remove driver's side and passenger's side ventilation louvers. Disconnect electrical connector for wiper motor. Remove bolts and wiper motor with wiper link assembly. Remove bolts and outer cowl top panel. Remove suspension upper brace. Suspension upper brace fits between strut towers and is bolted to top of each strut tower.
2. On ES300 and RX300 models, remove passenger's side front fender apron for access to crankshaft pulley. On all models, drain cooling system. Remove intake manifold cover. (Scheme 11)
3. Air intake chamber must be removed for removal of valve covers. Remove air cleaner cap assembly and air filter. Disconnect necessary electrical connections, control cables, PCV hose, coolant hoses, ground cables and vacuum hoses for removal of air intake chamber. (Scheme 11) Remove data link connector (DLC) No. 1 from end of air intake chamber.
4. Remove nuts and disconnect power steering pressure tube from No. 1 engine hanger. (Scheme 11) Remove bolts, No. 1 engine hanger and throttle body brace. (Scheme 11)
5. Remove bolts/nuts, air intake chamber and gasket. Disconnect electrical connectors at ignition coils. Remove bolts and ignition coils. Disconnect upper radiator hose from coolant outlet at front of engine, between cylinder heads.
6. Disconnect electrical connectors for removal of wiring assemblies located above valve covers. Remove bolts/nuts and wiring assemblies. Remove bolts, valve covers and gaskets.
7. Rotate crankshaft pulley clockwise (viewed from front of engine) so crankshaft pulley timing mark (groove) aligns with "0" mark on timing belt cover and cylinder No. 1 is at TDC on compression stroke. Cylinder No. 1 is front cylinder on right side of engine when viewed from flywheel end of engine. (Scheme 12)
8. Ensure cylinder No. 1 intake and exhaust valve lifters are loose. If valve lifters are not as described, rotate crankshaft clockwise one full revolution (360 degrees) and realign crankshaft pulley timing mark (groove) with "0" mark on timing belt cover.
9. Using feeler gauge, measure valve clearance between valve lifter and camshaft on intake valves on cylinders No. 1 and 6, and exhaust valves on cylinders No. 2 and 3. Perform STEP 1. (Scheme 12) Record valve clearance.
10. Rotate crankshaft pulley clockwise an additional 240 degrees (2/3 revolution). Measure valve clearance of intake valves on cylinders No. 2 and 3, and exhaust valves on cylinders No. 4 and 5. Perform STEP 2. (Scheme 12) Record valve clearance.
11. Rotate crankshaft pulley clockwise an additional 240 degrees (2/3 revolution). Measure valve clearance of intake valves on cylinders No. 4 and 5, and exhaust valves on cylinders No. 1 and 6. Perform STEP 3. (Scheme 12) Record valve clearance.
12. Ensure valve clearance is within specification. See «VALVE CLEARANCE SPECIFICATIONS (ES300 & RX300)»(ref-11537-S08995042732000111700000) table. VALVE CLEARANCE SPECIFICATIONS (ES300 & RX300) Application (1) In. (mm) Intake.006-.010 (.15-.25) Exhaust.010-.014 (.25-.35) (1) Adjust valve clearance with engine cold.
13. If valve clearance adjustment is required, rotate crankshaft pulley so camshaft lobe on valve to be adjusted is facing upward, away from valve lifter. Rotate valve lifter so notch area on valve lifter is at 90-degree angle to camshaft. This will place notch area perpendicular to camshaft.
14. Valve Clearance Adjuster (SST 09248-55040) is used to remove adjusting shim. Using SST "A" of valve clearance adjuster, press valve lifter downward. (Scheme 13) Install SST "B" between camshaft and valve lifter with side marked with "7" or "9" in the proper location, depending on cylinder application. (Scheme 13) Side marked with "7" should be used on front valves on cylinders No. 1 and 2 only. Side marked with "9" should be used on all except front valves on cylinders No. 1 and 2. Remove SST "A".
15. Using small screwdriver and magnet, remove adjusting shim. Using micrometer, measure and record thickness of removed adjusting shim. Using measured clearance and adjusting shim thickness, determine correct thickness of adjusting shim to be used. (Scheme 15)and (Scheme 16).
16. Install replacement adjusting shim with imprinted numbers on adjusting shim facing downward, toward valve lifter. Using SST "A", press downward on valve lifter and remove SST "B". Recheck valve clearance.
17. If spark plug tube gasket in valve cover requires replacement, bend gasket retaining tab upward. Pry spark plug tube gasket from valve cover. Use care not to scratch valve cover sealing surface.
18. Using hammer and proper sized bushing driver, tap spark plug tube gasket into valve cover until spark plug tube gasket is even with valve cover surface. Bend retaining tab downward. Coat spark plug tube gasket sealing area with grease.
19. Before installing valve covers and gaskets, apply sealant at specified areas on cylinder head. (Scheme 14) Install gasket and valve cover. Install and tighten valve cover bolts to specification. See «TORQUE SPECIFICATIONS»(ref-11537-S28228535062000111700000). To install remaining components, reverse removal procedure using NEW gaskets. Tighten bolts/nuts to specification. See «TORQUE SPECIFICATIONS»(ref-11537-S28228535062000111700000). Fill cooling system.

Scheme 14

Scheme 15

Scheme 16

Scheme 17

Scheme 18

Scheme 19

Scheme 20

Scheme 21

1. Drain cooling system. Remove air intake pipe for access to intake air connector with throttle body. (Scheme 17) Disconnect necessary electrical connectors, control cables, hoses and engine wire clamps for removal of intake air connector with throttle body.
2. Note location of throttle body bracket. (Scheme 17) Remove throttle body bracket-to-cylinder head nuts. Remove intake air connector-to-air intake chamber bolts/nuts. Remove air intake connector with throttle body and gasket from air intake chamber.
3. Remove oil filler cap. Remove bolts and upper timing belt cover with gasket. Disconnect electrical connectors from ignition coils, located above the spark plugs, in between the valve covers. Remove bolts and ignition coils with spark plug wires. Remove spark plugs.
4. Disconnect engine wiring harness for access to valve covers. Remove bolts/nuts, valve covers and gaskets.
5. Rotate crankshaft pulley clockwise so crankshaft pulley timing mark (groove) aligns with "0" mark on timing belt cover and cylinder No. 1 (front cylinder) is at TDC on compression stroke. Ensure timing marks on camshaft sprockets are aligned with timing marks on timing belt cover. (Scheme 18) If timing marks are not aligned, rotate crankshaft pulley clockwise one full revolution (360 degrees) and realign crankshaft pulley timing mark (groove) with "0" mark on timing belt cover.
6. Using feeler gauge, measure and record valve clearance of intake valves on cylinders No. 1, 2 and 4, and exhaust valves on cylinders No. 1, 3 and 5. Perform STEP 1. (Scheme 19)
7. Rotate crankshaft pulley clockwise one full revolution (360 degrees) and realign crankshaft pulley timing mark (groove) with "0" mark on timing belt cover. Using feeler gauge, measure and record valve clearance of intake valves on cylinders No. 3, 5 and 6, and exhaust valves on cylinders No. 2, 4 and 6. Perform STEP 2. (Scheme 19)
8. Ensure valve clearance is within specification. See «VALVE CLEARANCE SPECIFICATIONS (GS300 & IS300)»(ref-11537-S40881944302000111700000) table. VALVE CLEARANCE SPECIFICATIONS (GS300 & IS300) Application (1) In. (mm) Intake.006-.010 (.15-.25) Exhaust.010-.014 (.25-.35) (1) Adjust valve clearance with engine cold.
9. If valve clearance adjustment is required, rotate crankshaft pulley so camshaft lobe is facing upward on valve to be adjusted. Rotate valve lifter so notch area on valve lifter is at 90-degree angle to camshaft. This will place notch area perpendicular to camshaft.
10. Valve Clearance Adjuster (SST 09248-55040) is used for adjusting valve clearance. Press valve lifter downward using SST "A" of valve clearance adjuster. (Scheme 20) Install SST "B" between camshaft and valve lifter with side marked with No. 7 or No. 9 at designated position. (Scheme 20) Remove SST "A". NOTE: When adjusting valve clearance on intake valve on cylinder No. 1, it may be necessary to remove No. 2 camshaft bearing cap so SST "B" may be installed between camshaft and valve lifter.
11. Using small screwdriver and magnet, remove adjusting shim. Using micrometer, measure thickness of removed adjusting shim. Using measured clearance and adjusting shim thickness, determine correct thickness of adjusting shim to be used. (Scheme 15)and (Scheme 16).
12. Install proper adjusting shim with imprinted numbers on adjusting shim facing downward, toward valve lifter. Using SST "A", press downward on valve lifter and remove SST "B". Recheck valve clearance.
13. Install No. 2 camshaft bearing cap if removed. Tighten camshaft bearing cap bolts to specification. See «TORQUE SPECIFICATIONS»(ref-11537-S28228535062000111700000).
14. To install remaining components, reverse removal procedure using NEW gasket for air intake connector. Before installing valve covers and gaskets, apply sealant at specified areas on cylinder head. See. (Scheme 21). Tighten bolts/nuts to specification. See «TORQUE SPECIFICATIONS»(ref-11537-S28228535062000111700000). Fill cooling system.

Scheme 22

Scheme 23

Scheme 24

1. Remove intake manifold cover located on top of engine. Drain cooling system if any coolant hoses must be disconnected for access to valve covers. Remove air cleaner assembly (if necessary) and all necessary air intake hoses for access to valve covers.
2. On LX470, remove bolts/nuts and upper timing belt cover from front of each cylinder head at each camshaft. On all models, disconnect electrical connector at each ignition coil. Remove bolts and ignition coils from valve covers. Disconnect necessary hoses, hose brackets and engine wiring brackets for access to valve covers. Remove bolts, seal washers, valve covers and gaskets.
3. Rotate crankshaft pulley clockwise (viewed from front of engine) so crankshaft pulley timing mark (groove) aligns with "0" mark on lower timing belt cover and cylinder No. 1 is at TDC on compression stroke. Cylinder No. 1 is front cylinder on left side of engine when viewed from flywheel end of engine. (Scheme 22)
4. On GS430 and LS430, ensure timing marks on back of camshaft sprockets are aligned. (Scheme 23) On LX470, ensure timing marks on camshaft sprockets are aligned with timing marks on timing belt rear plate. (Scheme 24) On all models, if timing marks are not aligned, rotate crankshaft clockwise one full revolution (360 degrees) and realign crankshaft pulley timing mark (groove) with "0" mark on lower timing belt cover.
5. Using feeler gauge, measure valve clearance between valve lifter and camshaft on intake valves on cylinders No. 1, 2, 5, 7 and 8, and exhaust valves on cylinders No. 1, 4 and 8. Perform STEP 1. (Scheme 22) Record valve clearance.
6. Rotate crankshaft pulley clockwise one full revolution (360 degrees). Using feeler gauge, measure valve clearance between valve lifter and camshaft on intake valves on cylinders No. 3, 4 and 6, and exhaust valves on cylinders No. 2, 3, 5, 6 and 7. Perform STEP 2. (Scheme 22) Record valve clearance.
7. Ensure valve clearance is within specification. See «VALVE CLEARANCE SPECIFICATIONS (GS430, LS430 & LX470)»(ref-11537-S42199663822000111700000) table. VALVE CLEARANCE SPECIFICATIONS (GS430, LS430 & LX470) Application (1) In. (mm) Intake.006-.010 (.15-.25) Exhaust.010-.014 (.25-.35) (1) Adjust valve clearance with engine cold.
8. If valve clearance adjustment is required, adjusting shim between valve lifter and valve stem must be changed. To remove valve lifter, remove timing belt and camshafts. See CAMSHAFT under REMOVAL & INSTALLATION in appropriate ENGINES article.
9. Remove valve lifter and adjusting shim from valve. Using micrometer, measure thickness of adjusting shim removed. Using measured clearance and adjusting shim thickness, determine correct thickness of adjusting shim to be used. (Scheme 25)- (Scheme 26). Install adjusting shim, valve lifter, camshafts and timing belt. Recheck valve clearance.
10. If spark plug tube gasket in valve cover requires replacement, bend gasket retaining tabs upward. Pry spark plug tube gasket from valve cover. Use care not to scratch valve cover sealing surface.
11. Using hammer and proper sized bushing driver, tap spark plug tube gasket into valve cover until spark plug tube gasket is even with valve cover surface. Bend retaining tabs downward. Coat spark plug tube gasket sealing area with grease.
12. Before installing valve covers and gaskets, apply sealant at specified areas on cylinder head. (Scheme 27) Install gasket, valve cover, seal washers and valve cover bolts. Install and tighten valve cover bolts to specification in several steps. See «TORQUE SPECIFICATIONS»(ref-11537-S28228535062000111700000).
13. To install remaining components, reverse removal procedure. Tighten bolts/nuts to specification. See «TORQUE SPECIFICATIONS»(ref-11537-S28228535062000111700000). Refill cooling system if drained.

Scheme 25

Scheme 26

Scheme 27

IGNITION TIMING

Note. Data link connectors No. 1 or 3 may also be referred to as DLC1 or DLC3.

1. Remove intake manifold cover. (Scheme 11) Start and warm engine up to normal operating temperature. Shut engine off. Connect scan tool to DLC3. (Scheme 28) Use scan tool to read engine RPM.
2. Connect timing light lead to Black/Red wire at ignition coil electrical connector on top of front valve cover at cylinder No. 4. (Scheme 29) Open wiring harness cover to gain access if necessary. Cylinder No. 4 is second cylinder on left side when viewed from flywheel end of engine. (Scheme 12)
3. Apply parking brake. Place transaxle in Neutral. Start engine and maintain engine at 2500 RPM for 90 seconds and allow engine to idle. Ensure idle speed is 650-750 RPM.
4. Install Jumper Wire (SST 09843-18020) between terminals TE1 and E1 on DLC1. (Scheme 30)- (Scheme 31). DLC1 is located on end of air intake chamber at passenger's side of engine compartment.
5. Timing marks are located on timing belt cover, near crankshaft pulley. Ensure base timing is 8-12 degrees BTDC at idle with transaxle in Neutral, and with A/C and all accessories off.
6. Remove jumper wire from DLC1. Ensure ECM controlled timing is 10-25 degrees BTDC. Shut engine off. Remove timing light and scan tool. Reinstall intake manifold cover.

Scheme 28

Scheme 29

Scheme 30

Scheme 31

GS300 & IS300

1. Start and warm engine up to normal operating temperature. Shut engine off. Connect scan tool to DLC3. (Scheme 28) Use scan tool to read engine RPM. Using a timing light that can detect primary ignition signal, connect inductive lead to appropriate wire at ignitor. (Scheme 32) Ignitor is located on top of driver's side strut tower.
2. Apply parking brake. Place transmission in Neutral. Start engine and maintain engine at 2500 RPM for 90 seconds and allow engine to idle. Ensure idle speed is 650-750 RPM. Install Jumper Wire (SST 09843-18020) between terminals TC and E1 on DLC1 located near driver's side strut tower. (Scheme 33)
3. Timing marks are located on timing belt cover, near crankshaft pulley. Ensure base timing is 8-12 degrees BTDC at idle with transmission in Neutral, and with A/C and all accessories off. Remove jumper wire from DLC1. Ensure ECM controlled timing is 6-16 degrees BTDC. Shut engine off. Remove timing light and scan tool.

Scheme 32

Scheme 33

LX470

1. Start and warm engine up to normal operating temperature. Shut engine off. Remove intake manifold cover located on top of engine, battery clamp cover and intake air connector. Connect scan tool to DLC3. (Scheme 28) Use scan tool to read engine RPM.
2. Connect timing light lead to wire at ignition coil electrical connector on top of driver's side valve cover at cylinder No. 1. (Scheme 34) Cylinder No. 1 is front cylinder on left side of engine when viewed from flywheel end of engine. (Scheme 22)
3. Apply parking brake. Place transmission in Neutral. Start engine and maintain engine at 2500 RPM for 90 seconds and then allow engine to idle. Ensure idle speed is 650-750 RPM.
4. Install Jumper Wire (SST 09843-18020) between terminals TC and E1 on DLC1 located on passenger's side front fender. (Scheme 35)
5. Check timing marks located on timing belt cover, near crankshaft pulley. Ensure base ignition timing is 5-15 degrees BTDC at idle with transmission in Neutral. Shut engine off. Remove jumper wire, timing light and scan tool. Reinstall intake manifold cover, battery clamp cover and intake air connector.

Scheme 34

Scheme 35

IDLE SPEED & MIXTURE

Note. Mixture adjustment is not possible on any model.

IDLE SPEED

Note. Idle speed is controlled by Engine Control Module (ECM) and is not adjustable. Check idle speed with air cleaner installed, all air induction system hoses and vacuum lines connected, electronic fuel injection system wiring connectors properly installed, transmission/transaxle in Neutral, ignition timing properly set, A/C and all accessories off, and engine at normal operating temperature.

Note. Data link connectors No. 1 or 3 may also be referred to as DLC1 or DLC3.

1. Start and warm engine up to normal operating temperature. Shut engine off.
2. Connect scan tool to DLC3. (Scheme 28) Use scan tool to read engine RPM.
3. Apply parking brake. Place transaxle in Neutral. Start engine and maintain engine at 2500 RPM for 90 seconds and then allow engine to idle. Ensure idle speed is 650-750 RPM.
4. If idle speed is not within specification, check Idle Air Control (IAC) valve, wiring, Engine Control Module (ECM) and air intake system. See IDLE AIR CONTROL (IAC) SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. Shut engine off. Remove scan tool.

GS300, IS300, GS430, LS430 & LX470

1. Start and warm engine up to normal operating temperature. Shut engine off. Connect scan tool to DLC3. (Scheme 28) Use scan tool to read engine RPM.
2. Apply parking brake. Place transmission in Neutral. Start engine and maintain engine at 2500 RPM for 90 seconds and then allow engine to idle. Ensure idle speed is within specification. See «IDLE SPEED SPECIFICATIONS»(ref-11537-S08406609782000111700000) table. IDLE SPEED SPECIFICATIONS Application Idle RPM GS300, IS300 & LX470 650-750 GS430 & LS430 700-800
3. If idle speed is not within specification, check air intake system for leaks. If air intake system is okay, check throttle body. See THROTTLE BODY under THROTTLE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article. Shut engine off. Remove scan tool.

Note. Throttle body lever adjustment must be performed if throttle body or idle air control valve is replaced, or if throttle body or idle air control valve is removed and reinstalled. Perform preliminary inspection to determine if throttle body lever adjustment must be performed. Throttle stop screws and throttle opener are preset. DO NOT alter throttle stop screw or throttle opener adjustment.

1. Disconnect electrical connector from TP sensor. Note electrical terminals on TP sensor. (Scheme 36) Apply vacuum to throttle opener.
2. Using ohmmeter, check resistance between specified terminals in relation to throttle position. See «TP SENSOR RESISTANCE (ES300 & RX300)»(ref-11537-S39095001052000111700000) table. Replace TP sensor as necessary if resistance is not within specification.

TP SENSOR RESISTANCE (ES300 & RX300) (1)

Scheme 36

Adjusting TP Sensor

Note. Data link connectors No. 1 or 3 may also be referred to as DLC1 or DLC3.

1. Loosen 2 sensor mounting screws. Turn TP sensor until it no longer contacts throttle valve shaft. Turn TP sensor back until it just starts to touch throttle valve shaft, then snug mounting screws. On GS300, IS300 and LX470, disconnect accelerator pedal position sensor connector. On all models, connect scan tool to DLC3. (Scheme 28) Go to next step.
2. Turn ignition switch on. DO NOT depress accelerator pedal. On scan tool, select CURRENT DATA, then THROTTLE POS. Slowly turn TP sensor until value is as specified. See «TP SENSOR SPECIFICATIONS»(ref-11537-S03285602812000112900000) table. Tighten sensor mounting screws. Go to next step. TP SENSOR SPECIFICATIONS Model Scan Tool Value (Percent) GS300 & IS300 14.0-15.6 GS430, LS430 & LX470 14.4-16.0
3. Using screwdriver where necessary, push throttle valve completely closed. Recheck scan tool TP sensor value. Value should be 10-14 percent. If value is not as specified, go back to step 1. If value is as specified, on GS300, IS300 and LX470, reconnect accelerator pedal position sensor connector.

Scheme 37

1. Start and warm engine up to normal operating temperature. Shut engine off. Connect scan tool to DLC3. (Scheme 28) Use scan tool to read engine RPM.
2. Apply parking brake. Place transaxle in Neutral. Start engine and maintain engine at 2500 RPM for 90 seconds and then allow engine to idle. Ensure idle speed is 650-750 RPM.
3. Shut engine off. Disconnect and plug vacuum hose at throttle opener near throttle body. (Scheme 37) Start engine and note engine speed. Engine speed should be 1100-1700 RPM.
4. If engine speed is not within specification, replace throttle body. Shut engine off. Reinstall vacuum hose on throttle opener. Start engine and ensure engine returns to proper idle speed.

RX300

1. Testing information is not available from manufacturer.

PARK/NEUTRAL POSITION (PNP) SWITCH

For adjustment of PNP switch, see PARK/NEUTRAL POSITION (PNP) SWITCH under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article.

ES300

TORQUE SPECIFICATIONS (ES300)

TORQUE SPECIFICATIONS (GS300 & IS300)

GS430, LS430 & LX470

TORQUE SPECIFICATIONS (GS430, LS430 & LX470)

TORQUE SPECIFICATIONS (RX300)