Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSLEXUS1999RX 300 AWD V6-3.0L (1MZ-FE)REPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSTESTING AND INSPECTIONCOMPONENT TESTS AND GENERAL DIAGNOSTICSIACV CONTROL CIRCUIT
1999 Lexus RX 300 AWD V6-3.0L (1MZ-FE)
IACV Control Circuit
1999 Lexus RX 300 AWD V6-3.0L (1MZ-FE)SECTION IACV Control Circuit
CIRCUIT DESCRIPTION
This circuit opens and closes the IACV (Intake Air Control Valve) in response to the engine load in order to increase the intake efficiency (ACIS: Acoustic Control Induction System).
When the engine speed is 3,700 rpm or less and the throttle valve opening angle is 30° or more, the ECM turns the two VSV ON or OFF and operate the IACV.
INSPECTION PROCEDURE
Step 1:
Step 2:
Step 3:
LEXUS hand-held tester
Step 1:
Step 2:
Step 3:
OBD II scan tool (excluding LEXUS hand-held tester)
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.