Circuit Description

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The position of the turbocharger vanes is controlled by the engine control module (ECM). The ECM utilizes a turbocharger vane control solenoid valve and a turbocharger vane position sensor to control the turbocharger vanes. When the engine is not under load, the turbocharger vanes are in an open position, or no boost condition. When the engine is under load, the ECM commands the control solenoid valve to close the turbocharger vanes, thus increasing the boost. The ECM will vary the boost dependant upon the load requirements of the engine. The vane control solenoid valve uses 2 circuits, a control circuit and a low reference circuit. The ECM uses a pulse width modulation (PWM) on the control circuit to control the solenoid valve. The ECM provides a ground on the low reference circuit. If the ECM detects that the commanded position of the turbocharger vanes does not match the actual position, DTC P0046 will set.