Problem with high fuel consumption and check engine light on Peugeot 408 petrol 2014: Possible problem with the secondary air valve

Hi mate, I had a similar problem with my 2012 Peugeot 406, I also only have about average car experience. When the check engine light came on and I noticed the fuel consumption was high, I took it to my garage. It turned out that the electric changeover valve (EUV) was faulty, which controls the secondary airflow. I was told that it explained the high fuel consumption and the strong exhaust smell. The repair cost me 140 euros. Would you be able to tell me the exact type of fuel and what information do you get from the on-board computer? That would help to give you more tips. Do you wait a long time before the on-board computer throws an error message? The more information you can provide, the better we can help you. Cheers!

(Translated from German)

Hey, thanks for your answer! I always fill up with Super 95, and my on-board computer only tells me that there is a problem with the exhaust gas recirculation. I don't want to mess around with waiting too long, I did a small service a month or so ago at 29987 kilometers. Have you still had problems after the repair? And do you know if there might be a difference between our 408 and your 406? Cheers back!

(Translated from German)

Hey, no problem, help where you can, right? Well, if your on-board computer is already muttering something about exhaust gas recirculation and you suspect the secondary air valve, you could definitely be thinking in the right direction. After my EUV was replaced, my 406 ran like clockwork again. Higher fuel consumption, strong exhaust smell - all gone. I have another tip for you. Why don't you check your air filter or have it done by a mechanic? A dirty air filter can also cause the symptoms you are experiencing. That would certainly be a cheaper solution than a new EUV. Differences between our 408 and my 406? Good question...Well, what I can think of off the top of my head are of course the updates and retrofits. But I think as far as the secondary air valve is concerned, the models are probably pretty similar. The devil is always in the detail, of course, so you'd have to make a precise comparison. So be sure to keep us up to date here on what you come up with. Good luck and see you then!

(Translated from German)

Hello, thank you for the good advice! I will definitely have the air filter checked, that sounds like a possibility. Good to know that the EUV can explain the high fuel consumption and strong exhaust smell. I'll probably take the car to the garage and see what they say. I'll keep you posted here on what the diagnosis is. And thanks again for the help, really great of you! See you then!

(Translated from German)