Checking the Flap Valve
Checking the flap valveIf basic boost pressure cannot be adjusted, check the following:
1 Remove the exhaust bend from the turbo unit and visually check that the flap valve is in good contact with the turbine housing.
2 Break the seal, remove the circlip and unhook the pushrod from the valve actuator arm.
3 Check that it is easy to move the arm.
4 Rectify if necessary and change the turbo unit.
5 Refit the circlip and seal the pushrod.