Variable Induction System: Testing and Inspection

VIAS

Description

SYSTEM DESCRIPTION






When the engine is running at low or medium speed, the power valve is fully closed. Under this condition, the effective suction port length is equivalent to the total length of the intake manifold collector's suction port including the intake valve. This long suction port provides increased air intake which results in improved suction efficiency and higher torque generation.

The surge tank and one-way valve are provided. When engine is running at high speed, the ECM sends the signal to the VIAS control solenoid valve. This signal introduces the intake manifold vacuum into the power valve actuator and therefore opens the power valve to two suction passages together in the collector.

Under this condition, the effective port length is equivalent to the length of the suction port provided independently for each cylinder. This shortened port length results in enhanced engine output with reduced suction resistance under high speeds.

The power valve is always open regardless of the engine speed when gear position is in N or P.

COMPONENT DESCRIPTION

Power Valve




The power valve is installed in intake manifold collector and used to control the suction passage of the variable induction air control system. It is set in the fully closed or fully opened position by the power valve actuator (1) operated by the vacuum stored in the surge tank. The vacuum in the surge tank is controlled by the VIAS control solenoid valve.

VIAS Control Solenoid Valve




The VIAS control solenoid valve (1) cuts the intake manifold vacuum signal for power valve actuator. It responds to ON/OFF signals from the ECM. When the solenoid is off, the vacuum signal from the intake manifold is cut. When the ECM sends an ON signal the coil pulls the plunger downward and feeds the vacuum signal to the power valve actuator.

CONSULT-III Reference Value in Data Monitor Mode






Wiring Diagram

EC-VIAS-01:

Diagrams: Other diagrams referred to by name within these diagrams can be found at Diagrams By Diagram Name. Diagrams By Diagram Name

Diagnosis Procedure

Step 1-2:

Step 2 (Continued)-5:

Step 5 (Continued)-10:

Component Inspection

VIAS CONTROL SOLENOID VALVE

With CONSULT-III
1. Reconnect harness connectors disconnected.
2. Turn ignition switch ON.
3. Perform "VIAS S/V-1" in "ACTIVE TEST" mode.




4. Check air passage continuity and operation delay time under the following conditions.

Without CONSULT-III




Check air passage continuity and operation delay time under the following
conditions.

VACUUM TANK
1. Disconnect vacuum hose connected to vacuum tank.
2. Connect a vacuum pump to the port A of vacuum tank.




3. Apply vacuum and make sure that vacuum exists at the port B.