Volvo V40 Oxygen Sensor Cable Defect

Sounds familiar. I had a similar issue with my Opel Astra. Check engine light, air-fuel ratio issues... turned out to be the O2 sensor. Have you checked the exhaust system for leaks?

Thanks, good to know. Did you also have connection issues or did you replace the entire sensor?

I tried cleaning the contacts first, but no luck. Ended up needing a new sensor. Given your mileage, it might be worth getting it checked at a workshop.

Thanks for the advice. I took it to the workshop, and you were right, the O2 sensor cable was defective. Repair cost was 95€. Problem solved!