IACV Control Circuit

3UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: IACV Control Circuit
- IACV Control Circuit

DESCRIPTION

This circuit opens and closes the Intake Air Control Valve (IACV) in response to the engine load in order to increase the intake efficiency (ACIS: Acoustic Control Induction System).

When the engine speed is 4700 rpm or more and the throttle valve opening angle is 60° or more, the IACV is open (VSV: OFF). At all other times, the IACV is closed (VSV: ON).





WIRING DIAGRAM





INSEPCTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (VSV FOR ACIS)





(a) Disconnect the vacuum hose from the port F on the VSV for ACIS.

(b) Connect the Techstream to the DLC3.

(c) Start the engine.

(d) Enter the following menus: Powertrain / Engine / Active Test / Active the VSV for Intake Control.

(e) Check the VSV's air flow when switching the VSV.

OK:





NG -- INSPECT VACUUM SWITCHING VALVE (OPERATION)
OK -- Continue to next step.

2. CHECK VACUUM HOSES (INTAKE MANIFOLD - VACUUM SWITCHING VALVE, VACUUM SWITCHING VALVE - INTAKE AIR CONTROL VALVE)

(a) Check the condition of the vacuum hoses between the intake manifold, VSV for ACIS and IACV.

(1) The vacuum hoses are connected securely.

(2) Vacuum hoses are not cranked or damaged.

OK:

The vacuum hoses are connected securely and not cracked or damaged.

NG -- REPAIR OR REPLACE VACUUM HOSES
OK -- Continue to next step.

3. INSPECT INTAKE AIR CONTROL VALVE

(a) Inspect the intake air control valve Testing and Inspection.

NG -- REPLACE INTAKE AIR CONTROL VALVE

OK -- REPLACE ECM

4. INSPECT VACUUM SWITCHING VALVE (OPERATION)





(a) Check that air flows from port E to the air filter.

(b) Apply positive (+) battery voltage across the terminals.

(c) Check that air flows from port E to port F.

NG -- REPLACE VACUUM SWITCHING VALVE
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (VACUUM SWITCHING VALVE - ECM, VACUUM SWITCHING VALVE - BODY GROUND)





(a) Disconnect the V2 VSV for ACIS connector.

(b) Disconnect the E4 ECM connector.

(c) Measure the resistance of the wire harness side connectors.

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

6. INSPECT EFI RELAY





(a) Remove the EFI relay from the engine room No. 2 relay block.

(b) Measure the resistance of the EFI relay.

Standard Resistance:





NG -- REPLACE EFI RELAY

OK -- REPLACE ECM Service and Repair