Fiat Doblo intermittent check engine light and stalling

I experienced a similar issue with my 2018 Opel Insignia, also diesel. The symptoms you describe—check engine light, stalling, and fuel composition errors—were almost identical. In my case, the diagnostic pointed towards the fuel mixture being off. Before jumping to conclusions about the fuel filter or a full system clean, I would advise that you check the cable and plug connections of the fuel system components. Are you familiar with the intricacies of the combustion chamber and the specific sensors involved in regulating fuel input? These can sometimes be the source of the error, as a defective connection can cause the sensors to send faulty readings.

Thanks for the advice! When you mention 'cable and plug connections,' are you referring to specific components? I'm not deeply familiar with the fuel system, but I'm willing to take a look. Could you perhaps point me to which sensors or connections are most likely to cause this sort of problem?

Certainly. When I referred to the connections, I was thinking specifically about the fuel pressure sensor and the oxygen sensor connectors. However, please exercise caution. While you can visually inspect the connectors for any signs of corrosion or damage, and even try cleaning them with a contact cleaner, diagnosing the root cause accurately often requires specialized tools to read the sensor data. Given the uncertainties, perhaps having a workshop perform a diagnostic check is the most prudent course of action. It would be a pity to make the problem worse!

Thanks again for the detailed suggestions. I followed your advice and took it to a workshop. Turns out it was indeed a defective cable or plug connection, as the error memory said. They cleaned the contact, and the error disappeared. The total cost was 95€ Saved me a lot of headache!