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.
System Description
| Sensor | Input signal to ECM | ECM function | Actuator | ||
|---|---|---|---|---|---|
| Crankshaft position sensor (POS) Camshaft position sensor (PHASE) |
Engine speed(1) | VIAS control | VIAS control solenoid valve | ||
| Mass air flow sensor | Amount of intake air | ||||
| Throttle position sensor | Throttle position | ||||
| Accelerator pedal position sensor | Accelerator pedal position | ||||
| Battery | Battery voltage(1) | ||||
| Engine coolant temperature sensor | Engine coolant temperature | ||||
|
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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.
Use the Manual With the Right Hardware
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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.
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