Spin Oxygen Sensor Faulty Connection

Hey, higher fuel consumption and a check engine light screams O2 sensor issues. Since you've got an error code pointing that way, it's even more likely. A bad connection is plausible. Has the exhaust system been inspected for leaks? That can mess with the air-fuel ratio and throw O2 sensor codes too.

I haven't specifically checked the exhaust for leaks. Would a leak in the exhaust system before the catalytic converter cause similar symptoms, like a faulty oxygen sensor signal?

Yep, exhaust leaks before the catalytic converter definitely throw off the O2 sensor readings. The sensor thinks there's too much oxygen in the exhaust, so the system dumps more fuel in. That's your higher fuel consumption. Given the mileage, and the error code, I'd recommend a workshop check of the exhaust system and the O2 sensor wiring and the sensor itself. Could be a simple fix or a new sensor time.

I appreciate the advice. I visited a workshop and they confirmed the oxygen sensor was aged, and the cable connection was defective. The repair, including a plug replacement, cost 95€. The check engine light is now off, and the fuel consumption is back to normal. Thanks again for your help.