Turbo Control Valve

How to detect a faulty wastegate valve

To check whether the component is serviceable, open the hood and secure it. Check whether the valve stem moves freely, by carefully moving it up/down. Then disconnect the hose which connects the turbocharger control valve to the wastegate valve, and try to blow it out. In this process, the lever of the component should be held in the lowest position. If the wastegate valve is okay, the hose should not pass the air.

The wastegate valve may be checked in another way. For this purpose, measure the turbocharger boost pressure, and compare the obtained value with the values specified in the technical documentation to the vehicle. Diagnostics is performed with a pressure gauge, a hose, and adapters. In order not to be distracted from driving, you will need an assistant to take the readings of the pressure gage at certain moment. The procedure is the following:

1. Connect one end of the hose to the corresponding outlet of the intake manifold, and the second end - to the pressure gage in the passenger compartment. It is important that the hose does not touch moving components, and does not impede their operation.
2. Start the engine and warm it up to the operating temperature.
3. Engage the fourth gear, and then increase the engine speed to 3,000 rpm.
4. Smoothly press the accelerator pedal to the floor, and hold the revs at the level stated above by engaging the braking system. To avoid damaging the discs and pads, as well as clutch elements, do not hold the brake pedal and the accelerator pedal pressed simultaneously for more than 5 seconds.
5. Check the readings of the pressure gauge. If they are not equal to the rated values, the wastegate valve, most likely, will have to be replaced.