Circuit/System Description

WARNING: This page is about a different variant/trim than selected.

The intake manifold tuning valve controls the length of the intake runners in the intake manifold. The intake manifold contains both long and short runners. The tuning valve controls only the short runners. When the valve is closed, the short runners are blocked, which forces the air through the long runners. This results in tuning effects in the manifold that increases the torque produced by the engine at lower engine speeds. When the valve is open, both the long runners and short runners are open, but the majority of the air travels through the short runners, since the air will naturally follow the shortest path into the cylinder. This allows the air to flow through the short runners, which results in increased torque at higher engine speeds.

Ignition voltage is supplied directly to the intake manifold tuning valve actuator. The engine control module (ECM) controls the valve actuator motor by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled up to a voltage. The ECM can determine if the control circuit is open, shorted to ground or shorted to a voltage by monitoring the feedback voltage signal.

The tuning valve actuator contains a position sensor, which outputs a pulse width modulated (PWM) signal, to detect the actual position of the tuning valve in relation to its commanded position. Variations in the duty cycle of the PWM signal enables the ECM to detect a physically broken, restricted or stuck tuning valve.