Turbocharger: Testing and Inspection

Turbocharger Learn

The engine control module (ECM) performs the turbocharger (TC) learn procedure automatically when the engine coolant temperature (ECT) is least 72°C (162°F). 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 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 TC Learn procedure and fails, DTC P003A, P2598 or P2599 may set.

If a TC Learn is not performed after a related turbocharger repair, the ECM will use a stored vane position value that may be invalid. The ECM may then cause a diagnostic to fail and set an invalid DTC. Certain enable criteria must be met for the ECM to perform this procedure.

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

* Turbocharger vane position control solenoid valve replacement

* Turbocharger vane position sensor replacement

* ECM replacement

* Turbocharger replacement

* Any service that disturbs the turbocharger components

Learn Procedure With the Tech 2

Note: 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 air conditioning (A/C) system is OFF.

* The vehicle is in Park or Neutral.

* Start and idle the engine.

* The ECT is greater 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 Module Setup Menu. Command the TC Learn ON for at least 5 s, then command it OFF. The system should have learned the new turbocharger position. The TC Vane Position Learn Status parameter should have toggled from In Progress to TC Learned.