This doesn't always result in a check engine light as the valve can still be blown open by the boost pressure. We have seen many valves with this problem (see image above). The other problem is that diaphragm retaining ring is made from very thin plastic that goes brittle with heat cycles, and eventually fails. This prevents the diaphragm from sealing with the same problems as mentioned above.
This particular failure also results in the valve falling apart upon removal from the turbo, though in extreme cases bits of plastic can enter the turbo and destroy it. Our alternative is a fully engineered solution offering both significantly improved reliability. Our valve is piston based, with no diaphragm to fail, and of all aluminium construction, it replaces the original unit with a pressure/vacuum operated piston valve that still also retains the desirable OEM ECU control over valve actuation. The valve has been proved on the VAG scene for many years. The spring is interchangeable for different levels of boost, and the solenoid is plug and play with the wiring harness which is included. Model: Mini Cooper S R60. This item is in the category "Vehicle Parts & Accessories\Car Tuning & Styling\Air Intake & Induction\Dump, Bypass & Blow-Off Valves".The seller is "amber-performance" and is located in this country: GB. This item can be shipped worldwide.