Circuit/System Description

The engine control module (ECM) performs the turbocharger learn procedure automatically when the enabling criteria have been met. After each ignition cycle and before the enable criteria have been met, the ECM will use the previously learned value. If the ECM does not have a previously learned value, it will default to a stored calibrated value.

The ECM commands the turbocharger vane control solenoid to position the turbocharger vanes and a turbocharger vane position sensor monitors the actual position of the vanes. The turbocharger valve can have an inherent offset drift due to aging. Once per driving cycle, during engine idling, the valve is closed and opened fully and the position of the valve is read at the closed position. If the mean offset learned value, at the closed valve position, is not within a calibrated range or the time taken to learn the mean offset learned value position is greater than a calibrated threshold, the corresponding "Turbocharger Boost Control Position Not Learned" fault will be set.