Peugeot 5008 Turbo Boost Issue

I had very similar symptoms on my 5008: check engine light, jerking, whistling noises. It sounds like a boost pressure issue. Have you checked the intake manifold for leaks or cracks? Also, inspect the cable and plug connection of the boost pressure sensor itself. A defective connection there can cause all sorts of problems with the turbo system. Is the hissing sound particularly loud when the engine is under load?

Thanks! I'll inspect the intake manifold. When you had similar symptoms, was the defective connection obvious, or did it require a more detailed inspection? Also, what do you mean by 'under load'? I am not an expert in car repairs.

On my 5008, the cable looked fine at first, but one of the pins in the plug was slightly bent, causing intermittent contact. By 'under load', I mean when the engine is working harder – accelerating uphill or carrying a heavy load. If the hissing is more pronounced then, it strengthens the suspicion of a leak or a faulty sensor connection. Since you're not deeply familiar with car mechanics, I would strongly suggest taking it to a workshop to get it properly diagnosed. It's better to be safe than sorry when dealing with the turbo system.

Thanks so much for the explanation and advice! I'll bring my Peugeot to a trusted workshop for a diagnosis and repair. The issue was a defective cable or plug connection of the boost pressure sensor. The final bill was 95€.