Peugeot 207 Check Engine Light Air Valve

Hey there. I had something similar happen with my 207, although I can't recall the exact year, but it sounds familiar. The check engine light was on constantly, and the diagnostics also pointed toward intake manifold issues. It might be worth taking a really close look at those vacuum hoses, even the ones you can't easily see. Those hoses can develop pinhole leaks that are tough to spot but cause havoc with the air/fuel mixture, kinda like a tiny hole in a balloon slowly leaking air. What kind of idle are you experiencing?

Thanks for the quick response! That's helpful. My idle is generally a bit rough and erratic, dipping noticeably at times, especially when the engine is cold. When you say 'really close look', what exactly do you mean? Any specific areas or techniques you'd recommend for finding those pinhole leaks? Did your diagnostics also immediately nail it down to a specific hose?

With a 'really close look,' I mean feeling along the entire length of the hose. Sometimes you'll feel a slight change in texture where there's a crack, even if you can't see it. In my case, the diagnostics didn't pinpoint one hose immediately, but rather a general area associated with the air valve like yours. Given your rough idle, it sounds increasingly plausible it's something similar. Honestly, I ended up taking it to a trusted workshop because I was running out of ideas and patience. They found a cracked hose connection on the pump, and it's not something I would have been able to identify on my own.

Thanks a lot for your insights and for sharing your experience! I'll definitely give the hoses another, more thorough check with your suggestion. Based on what you said, I think I'll just go straight to my preferred workshop; might safe some time and frustration. It was indeed the hose connection from the pump to the valve. Cost me 175€, but now the engine light is off.