DS5 Check Engine Light and Fuel Consumption

I had something similar on my DS5. The check engine light coming on and increased fuel consumption are definitely red flags. VANOS is a variable valve timing system, it optimizes engine performance and efficiency. A faulty VANOS solenoid valve can cause these issues, as the valve controls the oil flow to the VANOS actuator, which adjusts the camshaft timing. Have you noticed any low power or rough idling?

Thanks for the reply! No rough idling, but I have noticed a slight decrease in power, especially when accelerating. Could it be the timing chain as well, or is that less likely?

A stretched timing chain could cause similar symptoms, but it's less common. The fact that you are experiencing power loss along with the check engine light and increased fuel consumption points to the VANOS solenoid. To be sure it’s the solenoid, you can check the power being supplied to it. Really though, for something like this, it's best to get it checked by a workshop. They can properly diagnose the issue and prevent further damage.

Okay, thanks for the advice. I took it to a local garage, and you were spot on. It was the inlet VANOS solenoid, and they replaced it. The total cost was 250€, which I thought was reasonable. The car is running much better now. Thanks again!