WARNING: This page is about a different car, the 2004 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT INTAKE AIR CONTROL VALVE ACTUATOR

Fig 1: Inspecting Intake Air Control Valve Actuator
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. (a) Connect the MITYVAC (hand-held vacuum pump) to the actuator.
2. Apply a vacuum of 39.9 kPa (300 mmHg, 11.8 in. Hg) to the actuator and check that the actuator rod moves.
3. 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.
INSPECT VACUUM TANK

Fig 2: Inspecting Vacuum Tank
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. Connect the MITYVAC (hand-held vacuum pump) to port A.
2. Apply a vacuum of 66.7 kPa (500 mmHg, 20 in. Hg) to the vacuum tank.
3. 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.
INSPECT VACUUM SWITCHING VALVE ASSY FOR IAC VALVE
1. Measure the VSV resistance.
  Standard:
  
  Fig 3: VSV Resistance Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  If the resistance is not as specified, replace the VSV assy.
  
  Fig 4: Measuring VSV Resistance
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. 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 5: Checking Air Flows From Port E To Filter
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. Apply battery positive voltage across the terminals.
  3. Check that air flows from port E to port F.
  If the result is not as specified, replace the VSV assy.
  
  Fig 6: Checking Air Flows From Port E To Filter
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply: