2011 Fabia Greenline II CR, 95K miles
I've seen a couple threads of people discussing why Auto start/stop stops working in their cars after a while. The conditions are met but they still don't work after a while. The general suggestion found on this forum is to replace the battery as it gets old.
I cannot see actual age of battery, but I get 12.##v with the car off, and 14.##v when on, suggesting alternator is working and battery health is ok. But I've had "Start/Stop Not Possible" message from the time I bought the car. I didn't care for it. And often pressed the button to turn it off as I'm still in testing phase of this car and observing other matters.
The car needed a blower resistor as I could only use the fan on 4, and as I have a misting/condnsation problem, I need to use the fan longer on lower setting (4 is just annoying. I don't like noise). So I got the replacement part, a generic resistor, and replaced that.
In order to do that you need to have the battery disconnected (so I lost my trip and MPG mesurement and whatnot but to hell with that).
I started the car when I was done with fitting the new resistor, and with the fan blowing smoothly on 1, took on a 5-mile round trip, and to my suprise, Auto Start/Stop just kicked in. I drove for over 2 miles with my jaw wide open and eyebrows as high as they can get.
I believe it had more to do with the car or ECU being "reset" due to battery disconnection for a while, which may be what people who change their batteries ultimately do: they disconnect the battery for a few minutes while it gets replaced. So is it really replacing an old healthy battery with a new one that is making the system kick back in, as was suggested here by someone, or is it merely disconnecting the battery, and reconnecting it a healthy energy source regardless of age.
I don't know if this will be a correct assessment, but it may help someone out there or help give a better perspective on this particular issue, which seems to be fairly common in this car model.
Best of luck.