LEXUS LS430 2003 Factory Repair Manual

Fig. 2: Identifying Intake Air Control System Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
ON-VEHICLE INSPECTION
1.INSPECT INTAKE AIR CONTROL FUNCTION

Fig. 3: Inspecting Intake Air Control Function
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
a. Remove the V-bank cover.
b. Connect the hand-held tester (with CAN VIM) to the DLC3.
c. Perform the ACTIVE TEST, and then check that the actuator rod operates.
d. Start the engine.
e. Check that the VSV for IAC valve in ON (seal) under these conditions.
Depressing the accelerator pedal to a throttle valve opening angle of 60 degrees.
Racing the engine above 4,700 rpm.
f. Check that the VSV for IAC valve is OFF (vent) under these conditions.
The engine is idling.
Releasing the accelerator pedal while under the 2 conditions in step (e).
If the result is not as specified, inspect the IAC valve, vacuum tank and VSV for normal operation.
Replace malfunctioning parts as necessary.
INSPECTION
1.INSPECT INTAKE AIR CONTROL VALVE ACTUATOR
a. Connect the MITYVAC (han
d-held vacuum pump) to the actuator.

b. Apply a vacuum of 39.9 kPa (300 mmHg, 11.8 in.Hg) to the actuator and check that the actuator
rod moves.
c. One minute after applying the vacuum, check that the rod's position is the same as in step (a).
If the result is not as specified, replace the IAC valve actuator.
Fig. 4: Inspect Intake Air Control Valve Actuator

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
2.INSPECT VACUUM TANK
a. Connect the MITYVAC (hand-held vacuum pump) to port A.
b. Apply a vacuum of 66.7 kPa (500 mmHg, 20 in.Hg) to the vacuum tank.
c. One minute after applying the vacuum, check that the pressure does not change.
If the result is not as specified, replace the vacuum control valve set.

Fig. 5: Inspecting Vacuum Tank
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
3.INSPECT VACUUM SWITCHING VALVE ASSY FOR IAC VALVE
a. Measure the VSV resistance.

Fig. 6: Measuring VSV Resistance
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Standard:

VACUUM SWITCHING VALVE ASSY FOR IAC VALVE
If the resistance is not as specified, replace the VSV assy.
b. Check the VSV operation.
1. Check that air flows from port E to the filter.
If the result is not as specified, replace the VSV assy.
Fig. 7: Checking Air Flows From Port E To Filter

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2. Apply battery positive voltage across the terminals.
3. Check that air flows from port E to port F.
Tester ConnectionSpecified Condition
1 - 233 to 39 ohms at 20°C (68°F)
1 - Body ground, 2 - Body ground10 kohms or higher

If the result is not as specified, replace the VSV assy.
Fig. 8: Checking Air Flows From Port E To Port F

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REPLACEMENT
1.DRAIN ENGINE COOLANT
2.WORK FOR PREVENTING GASOLINE FROM SPILLING OUT
3.REMOVE V-BANK COVER
a. Remove the 2 nuts and V-bank cover.
4.REMOVE AIR CLEANER INLET NO. 1
5.REMOVE INTAKE AIR CONNECTOR PIPE
a. Disconnect the air hose and ventilation hose No. 1.
b. Remove the bolt, hose clamp and intake air connector pipe.

6.REMOVE THROTTLE BODY ASSY
a. Disconnect the connector from the throttle body.
b. Disconnect the PCV hose.
c. Disconnect the 2 water by-pass hoses.
HINT:
It is not necessary to disconnect the water by-pass hose that has both ends connected to the throttle
body.
d. Remove the 2 bolts, 2 nuts and throttle body.
7.REMOVE V-BANK COVER BRACKET NO. 1
a. Remove the bolt and cover bracket.
8.REMOVE V-BANK COVER BRACKET NO. 2
a. Remove the bolt and cover bracket.
9.REMOVE V-BANK COVER BRACKET NO. 3
a. Remove the bolt and cover bracket.
10.REMOVE V-BANK COVER BRACKET NO. 4
a. Remove the 2 nuts and cover bracket.
11.REMOVE VACUUM SWITCHING VALVE ASSY FOR EVAP
a. Disconnect the VSV connector.
b. Disconnect the 2 hoses from the VSV.
c. Remove the bolt and VSV.
12.DISCONNECT FUEL PIPE SUB-ASSY NO. 2
a. Using SST, disconnect the fuel main hose.
SST 09023-38401

Fig. 9: Disconnecting Fuel Pipe Sub-Assy No. 2
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
13.REMOVE INTAKE MANIFOLD
a. Remove the bolt and the water by-pass pipe No. 1 and No. 2.
b. Disconnect the vacuum hose for the brake booster.
c. Disconnect the air hose for the power steering.
d. Disconnect the ventilation hose.
e. Disconnect the injector connector.
f. Remove the 6 bolts, 4 nuts and intake manifold.
14.REMOVE INTAKE MANIFOLD TO HEAD GASKET NO. 1
15.INSTALL INTAKE MANIFOLD TO HEAD GASKET NO. 1
a. Install 2 new gaskets to the cylinder head.
HINT:
The white-painted area on each gasket should face up as shown in the illustration.

Fig. 10: Installing Intake Manifold To Head Gasket No. 1
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
16.INSTALL INTAKE MANIFOLD
a. Install the intake manifold with the 6 bolts and 4 nuts.
Torque: 18 N.m (184 kgf.cm, 13 ft.lbf)
b. Connect the injector connector.
c. Connect the ventilation hose.
d. Connect the air hose for the power steering.
e. Connect the vacuum hose for the brake booster.
f. Install the water by-pass pipe No. 1 and No. 2 with the bolt.
17.CONNECT FUEL PIPE SUB-ASSY NO. 2
a. Using SST, install the fuel main hose.
SST 09023-38401