Circuit/System Description

The engine control module (ECM) performs the turbocharger (TC) 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 learn value, it will default to a stored calibrated value. The ECM will use this value until the enable criteria have been met. The ECM performs the self learn by commanding the TC vanes to 0 percent, then to 100 percent, while monitoring the TC vane position sensor.

The position of the TC vanes are controlled by the ECM. The ECM utilizes a TC vane control solenoid valve (TC control solenoid) and a TC vane position sensor to control the TC vanes. The ECM will vary the boost dependant upon the load requirements of the engine. The vane control solenoid valve has 2 circuits, a high voltage control circuit and a low control circuit. The ECM uses a pulse width modulation (PWM) on the high control and low control circuits to control the solenoid valve. If the commanded vane position did not match the actual vane position by a calibrated threshold. The ECM will detect if the automatic TC learn has failed.