Description and Diagnostic Procedure

SYSTEM: Vacuum Switching Valve Circuit For Intake Air Control Valve

CIRCUIT DESCRIPTION



The circuit opens and closes the intake air control valve (IACV) in response to the engine load in order to increase the intake efficiency {Acoustic Control Induction System (ACIS)}.
When the engine speed is 4,500 rpm or less and throttle valve opening angle is 30°or more, or engine speed is 4,500 rpm or more and throttle valve opening angle is 30°or less, the ECM turns the Vacuum Switching Valve (VSV) ON and closes the intake air control valve. At all other times, the VSV is OFF, so the intake air control Valve is open.

DIAGNOSTIC PROCEDURE

Wiring Schematic For The VSV For ACIS Circuit:

1. CHECK OPERATION OF THE VSV FOR ACIS.
-> If OK proceed to step 2.
-> If not OK replace VSV.

2. CHECK VOLTAGE OF VSV POWER SOURCE.
-> If OK check vacuum tank operation.
-> If not OK proceed to step 3.

3. CHECK FOR OPEN AND SHORT IN VSV CIRCUIT.
-> If OK check and replace ECM.
-> If not OK repair or replace harness or connector.