Leakage of the pressurization system:
- check for leaks, cracks and breakage of the air pipe between the turbocharger and the intake manifold, passing through the intercooler, and eliminate possible malfunctions;
- check the tightness of the connection between the intake manifold and the head of the block. Malfunctions here are possible due to a leaky gasket or, in the worst case, due to a damaged manifold;
- Leaks can also occur at the connections between the exhaust manifold flange and the cylinder head or between the exhaust manifold and the turbocharger.
Faulty turbocharger:
- check the boost pressure at the service station. It can be high or, conversely, low. If the pressure is too high, the boost pressure control solenoid valve or fuel pressure control valve may be faulty. Diagnostics of the controller storage device at the service should show the source of the malfunction;
- if the pressure is too low, the diaphragm mechanism of the boost pressure control valve may be faulty. Otherwise, the turbocharger is faulty.