The turbocharger (TC) learns the vane positions automatically during each ignition cycle. The engine control module (ECM) performs the turbocharger learn procedure automatically when the enable criteria are met. After each ignition cycle, and before the enable criteria ha 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. It will then perform this procedure to learn the new value. If the ECM attempts to perform the learn procedure and fails, DTCs P0046 or P2563 may set.

The turbocharger learn procedure must be performed manually with a Tech 2 when any turbocharger system service has been performed. Certain enable criteria must be met for the ECM to perform this procedure.

The turbocharger learn procedure is required when the following service procedures have been performed:

Important: Once the enable conditions have been met the throttle must remain at idle. Do not change the accelerator pedal position (APP) during this procedure.

1. The following conditions must be met for the ECM to perform the turbocharger learn procedure:

•	The A/C is OFF.

•	The vehicle is in Park or Neutral.

•	Start and idle the engine.

•	The engine coolant temperature (ECT) is more than 40°C (104°F).

2. After the enable conditions have been met and the engine idle is stabilized, enter the TC Learn Output function from the Engine Output Control Menu. Command the TC Vane Position Sensor ON for at least 5 seconds, then command it OFF. The system should have learned the new turbocharger position. The TC Learned parameter should have toggled from No to Yes.