Turbocharger Wastegate Position Learning

Each engine cycle the ECM learns the position of the wastegate valve. Wastegate closed position learning strongly depends on the turbocharger temperature. Turbocharger operating conditions leading to thermal reference conditions at the turbocharger are easy to reproduce. The ECM learns the wastegate positions around 500°C (932°F) since the wastegate can be closed and very little to no boost pressure is provided. Therefore, the turbocharger wastegate closed position learning is only enabled, if the engine is fully warmed up and the coolant temperature is greater than 70°C (158°F). This strategy minimizes the effect of turbine housing temperature variations on the learned wastegate closed position under typical engine operating conditions, exhaust gas ~500°C (932°F) at idle to ~950°C (1742°F) at high engine loads, which also allows the ECM to account for component aging. Once the wastegate position has been learned during the ignition cycle, an update in the opening direction is only allowed once an ignition cycle in the case of increased engine loads, turbine housing temperature 950°C (1742°F). Updates in the closing direction are allowed continuously. No updates occur on deceleration. Green engine initial wastegate closed position learning is enabled at ignition On to acquire the raw Min/Max position, then again when the engine is fully warmed up for the first time.

The following reset or learn procedures are required whenever the turbocharger, wastegate actuator, related component or sensor is replaced or serviced;

• Turbocharger Wastegate Learn - turbocharger or actuator replacement
• Intake System Learned Values Reset - turbocharger, actuator replacement, related sensor, or intake air duct

  Perform the Reset or Learn only as directed by the appropriate procedure.