P0039 vehicle  problems with turbocharger or supercharger Turbo Charger Bypass Valve Control Circuit Range Performance  This diagnostic trouble code  is a generic OBD-II powertrain code. It is considered generic because it applies to all makes and models of vehicles , although specific repair steps may vary depending on the make and model.  A code P0039 Turbo Charger Bypass Valve Control Circuit Performance is stored in turbocharged and supercharged vehicles when the powertrain control module has detected a turbocharger or supercharger boost pressure bypass valve control circuit malfunction. A service engine soon lamp may also be illuminated.  The boost controller gathers input signals from various engine sensors and uses them to calculate the optimum degree of turbo boost pressure. The boost pressure bypass valve is then activated, using an electronic solenoid, electric motor, or vacuum control valve to achieve the desired amount of boost pressure. P0039 vehicle  problems with turbocharger or supercharger Turbo Charger Bypass Valve Control Circuit Range Performance  Turbo bypass control valve operation is normally accomplished using a solenoid or a small electric motor. Vacuum operated valves are used on some models but this is design is much less common. The PCM supplies a direct voltage signal in order to activate electronically controlled valves but vacuum actuated valves are controlled using a vacuum control  solenoid. The vacuum service solenoid is usually supplied with constant voltage and the PCM outputs a ground signal when the valve must be opened to relieve boost pressure. The valve closes automatically when the ground signal is stopped by the PCM. The vacuum actuated bypass valve is controlled using a voltage signal from the PCM applied to a vacuum service solenoid. Opening and closing the solenoid permits engine vacuum to the reach the valve to actuate opening. Consult the manufacturer’s service manual  for turbo bypass control system specifications before beginning a diagnosis. Code Severity & Symptoms.  A significant reduction in engine performance Hissing noises from  the supercharger Engine and transmission temperatures could be higher than normal. A bad PCM or boost controller Diagnostic and Repair Procedures A good starting point is always to check for technical service bulletins  for your particular vehicle.  Pursuant to maintaining an acceptable degree of turbo boost pressure, the boost pressure bypass control valve is designed to open and close to a calculated degree.