The turbocharger learn procedure is performed automatically during each ignition cycle by the engine control module (ECM). Certain enable criteria must be met for the ECM to perform this procedure. After each ignition cycle, and before the enable criteria for the learn procedure 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, and then it will perform the procedure to learn the new value. If the ECM attempt to perform the procedure and fails, diagnostic trouble codes (DTCs) P0046 or P2563 may set.

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 72°C (162°F).

2. After the enable conditions have been met for at least 60 seconds, turn OFF the ignition for at least 30 seconds. The system should have learned the new turbocharger position.