Twingo Boost Pressure Control Fault

Boost pressure issues on a relatively new Twingo aren't ideal. Has the car been regularly serviced? When did you last check the pressure sensor or vacuum lines for leaks? Could it be a faulty bypass valve? Is there any turbo lag or hissing sound?

Yes, it's had regular service. I haven't checked the pressure sensor or vacuum lines myself – I'm not sure where to find them on this engine. How can I diagnose the bypass valve? Any advice on finding a vacuum leak, besides listening for hissing?

If you're not familiar with the engine layout, investigating yourself might cause more harm. A vacuum leak is hard to pinpoint without the right tools. Assuming the air filter is okay, I'd guess a defect in a vacuum switching valve, given the symptoms and the car's age. A shop should diagnose it quickly, as it relates to boost pressure control. It's best to have it checked professionally to avoid bigger problems.

I took it to the workshop, and you were right! It was a faulty vacuum switching valve. The repair cost 140€. The car runs like new now. Thanks for the advice!