Insignia Start Stop Problems

I had a similar problem with my 2016 Peugeot 308, but not the exact same symptoms. The start-stop was just permanently disabled. Did you check the battery voltage? And does it only happen when the engine is cold, or all the time?

I haven't measured the battery voltage directly yet, but I plan to do that tomorrow. It seems to occur regardless of engine temperature. Cold or hot, makes no difference.

Okay, in my case the garage confirmed that the battery didn't hold enough charge anymore, which causes the start-stop to deactivate as a protection mechanism. Yours sounds more serious if the engine is actually cutting out. I'd still check the battery, but probably best to get it to a workshop.

I had the battery tested and replaced it with a new one for 290€. Seems to have solved it. It was indeed defective.