Circuit/System Description

WARNING: This page is about a different car, the 2015 Chevrolet Trax and 2015 Buick Encore. However, it is still accessible from the selected car via links, so may be relevant.

The turbocharger incorporates a wastegate that is controlled by a pressure differential, that is determined by the engine control module (ECM) by means of a PWM solenoid valve, in order to regulate the pressure ratio of the turbocharger. A turbocharger bypass valve also controlled by the ECM by utilizing a remotely mounted solenoid valve is integrated into the bypass valve to prevent turbocharger surging and damage from vibrations by opening during abrupt closed throttle conditions. When the valve is open during closed throttle deceleration conditions, the bypass valve allows the air to recirculate in the turbocharger and maintain turbocharger speed. Within a calibrated range during the closed throttle event, or upon a wide open throttle command the valve will then close to optimize turbo response. The bypass solenoid valve has the following circuits:

Ignition voltage
Turbocharger bypass solenoid valve control

As engine load and engine speed increases, the turbocharger bypass solenoid valve remains commanded ON by the ECM. As soon as the throttle closes the turbocharger bypass solenoid valve is commanded OFF by the ECM, in order to allow the turbocharger bypass valve to open and allow the turbocharger air to recirculate, there by preventing turbocharger surging.