Peugeot 807 oxygen sensor issue

Hey! A faulty O2 sensor can definitely cause those symptoms. Have you tried cleaning the contacts on the plug connection? Sometimes, just a bit of corrosion can mess things up. Also, is the error code pointing to a specific sensor – pre-cat or post-cat?

Thanks for the tip! I haven't cleaned the contacts yet, but will give that a try. The error code just says "oxygen sensor circuit malfunction", nothing specific about pre- or post-cat. If cleaning the contacts doesn't work, what should my next step be?

Okay, "oxygen sensor circuit malfunction" is pretty broad. If cleaning doesn't help, and given the mileage, it might just be an aged sensor. Could be the sensor itself is failing. At this point, I'd suggest taking it to a workshop to get a proper diagnosis. They can test the sensor and wiring more thoroughly.

Thanks for the advice! Cleaning the contacts didn't do the trick, so I took it to a local shop. Turns out, you were right – it was the cable connection to the O2 sensor causing the issue, and the sensor was aged. They replaced the plug and the sensor for around 95€. The check engine light is gone, and my fuel consumption is back to normal. Appreciate the help!