The exhaust gases are used by the turbocharger to generate the turbine operation. There is an exhaust manifold, whose design is specially created to allow exhaust gases from the engine to enter the turbocharger from the turbine side. On the other side of the turbocharger there is a casing, which is coupled to the intake manifold by means of aluminum or silicone hoses. With this design, the turbocharger can capture the exhaust gases, compress them at high temperatures and return them to the engine as forced air induction.
Turbocharged and supercharged vehicles use forced air induction to increase engine performance. These engines require a very particular fuel delivery as well as an engine management strategy. That’s why PCM is programmed for those needs.
Importantly, there is a risk of engine damage due to excessive boost pressure. That is why there is a discharge valve that regulates the pressure. This pressure is relieved as the intake system is vented by a vessel designed for this purpose.
The discharge valve is controlled by a solenoid. If the PCM observes an over-impulse condition, a voltage signal is applied to the discharge valve solenoid, the valve opens and the excess exhaust pressure can escape. DTC code P0046 OBD2 is activated when the PCM detects a performance problem with respect to the impulse control solenoid.