Peugeot 207 Oxygen Sensor Issue

That sounds awfully familiar! I have a 207 diesel as well, and I had almost the exact same issues a while back. Check engine light, error codes mentioning the O2 sensor… you name it. Before you tear into the wiring, have you noticed any changes in how the engine idles, like a rough idle, maybe some vibration? And the increased fuel consumption, is it significant, or just a slight increase? It could be a bunch of things.

The idle seems fine. As for the fuel consumption, I'd say it is about 10-15% higher than usual. Do you remember if your repair shop found a defective cable?

Ah, a substantial increase in fuel consumption, then. My mechanic back then suspected an issue with the O2 sensor, much like you mentioned. It turned out to be a faulty sensor connector. It is important to take care of it promptly, since it will affect your vehicle emissions. Just a heads up: I ended up needing to replace the whole O2 sensor. If I were you, I'd schedule an appointment with the workshop.

Thanks for the info. It's helpful to know someone else has experienced the same issue. I will take it to a workshop to get it inspected. They quoted 95€ for parts and labor, which seems reasonable. Hopefully, that will solve it.