C4 Boost Pressure Fault

Hello! I had similar symptoms on my C4, although it wasn't the same year model. It sounds like a potential issue with the turbo system. Did you notice any turbo lag or unusual sounds from the engine? Have you checked for any obvious vacuum leaks around the turbo?

Thanks for the quick reply! I do think I've noticed a slight turbo lag, especially when accelerating uphill. How did you resolve the issue? Was it a complicated fix?

Well, in my case, it turned out to be a defective vacuum switching valve controlling the turbocharger. It's a relatively inexpensive part, but it can cause all sorts of problems with boost pressure. Given your symptoms, it might be worth having a workshop check it out. I was lucky, but you can easily damage the turbocharger itself. My final repair bill amounted to around 140€

Okay, that's very helpful. I appreciate the advice! I'll take it to a workshop and mention the vacuum switching valve. Hopefully, it's a similar issue and not something more serious.