What does it mean?
OBD II fault code P0244 is a generic code that is defined as “Turbocharger (TC) wastegate regulating valve “A” – range/performance problem” or sometimes as “Turbocharger Wastegate Solenoid “A” Range/Performance”, and is set when the PCM (Powertrain Control Module) detects an unexpected, or out-of-specification voltage in the turbocharger wastegate control solenoid labelled as “A”.
Note that since twin-turbo applications may have more than one wastegate control solenoids, it is recommended that the manual for the affected application be consulted to locate and identify solenoid “A” correctly. Also known as boost control solenoids, the function of these solenoids is to control the wastegate on a turbo charger to prevent over boost conditions that could damage an engine.
In simple terms, a turbo charger is a compressor that uses the exhaust gas expelled from an engine to drive a compressor wheel, which compresses the intake air to force more air into the engine than is possible to do on a normally aspirated engine.
However, since the boost pressure any turbo charger develops is directly related to the speed and volume of the exhaust gas that drives the turbine side of the unit at any given moment, high engine speeds can lead to conditions where the boost pressure exceeds the engine’s ability to withstand excessively high boost pressures.
To prevent engine damage due to excessively high boost pressures, all turbo chargers are equipped with devices called “waste gates” or sometimes, “dump valves”, whose purpose it is either to relieve excess boost pressure, or to prevent excessive boost pressures from developing in the first place.
As the term implies, a waste gate is simply a door-like device within the turbo charger that opens when the boost pressure exceeds a specified limit, which has the effect of limiting or regulating the boost pressure. On modern boost control systems, the operation of the waste gate is most commonly controlled by a vacuum actuator that uses engine vacuum to pull the gate open via a control rod.
In order to control the boost pressure more accurately, the PCM uses input data from a dedicated boost pressure sensor (among other sensors), to make adjustments to the fuel delivery and ignition timing strategies to extract the most power from the additional intake air. However, since an engine can only cope with a fixed amount of intake air, the PCM monitors the boost pressure, and hence, the volume of air that enters the engine via several sensors.
When it detects a condition where the boost pressure exceeds a predefined maximum allowable limit, it commands the electrically operated boost pressure control solenoid open, which allows engine vacuum to act on the waste gate actuator to pull the waste gate open to dump excess boost pressure into the exhaust system.
In a fully functional system, the boost control solenoid opens and closes the turbo charger waste gate so efficiently that the boost pressure is for all practical purposes, kept at a near-constant value.
However, when any fault, defect, malfunction, or failure in the boost control solenoids’ control/signal circuits occurs that causes unexpected, implausible, or inaccurate input and/or signal voltages, the PCM recognizes that it cannot control the boost pressure via the waste gate effectively, and it will set code P0244 and illuminate a warning light as a result.