Fiat Doblo Oxygen Sensor Fault

That sounds frustrating! I had a similar problem with my 2016 Opel Astra diesel. The check engine light was constantly on, and diagnostics pointed to the O2 sensor (or lambda sensor). I checked the sensor itself and it seemed fine. I didn't have higher fuel consumption, but I noticed a slight hesitation during acceleration. Did you measure the voltage on the O2 sensor's signal wire to see if it's within the expected range? That might narrow down whether the sensor is truly faulty or if it's a wiring issue.

Thanks for the insight! I haven't measured the voltage yet, but that's a good suggestion. When you say 'expected range,' do you recall what that range was for your Astra's O2 sensor? Also, did the diagnostic error specifically point to a slow response from the O2 sensor, or was it a more general 'O2 sensor malfunction' code? Any extra info could help!

I wish I could remember the exact voltage range, but it's been a while. If you can find the technical specifications for your Doblo's engine, it should be listed there. The error code was specific, indicating a 'slow response' from the O2 sensor, which made me suspect a wiring issue or a failing sensor heater. Given your higher fuel consumption, it sounds like the air-fuel ratio is off. I took mine to a workshop, and they confirmed a faulty connection. If you aren't comfortable doing these repairs yourself, I suggest getting it checked at a workshop.

Thanks so much for sharing your experience! It sounds like my Doblo's issue is similar to what you encountered with your Astra. I'll start by checking the voltage and the wiring harness, and if I can't find anything obvious, I'll probably take it to a workshop. Just got the car back from the shop. It was the cable to the O2 sensor. They charged me 95€ for the repair. Thanks again!