I just learned recently that Porsche had ACC in its pre-second-gen Panameras, Cayennes, etc. -- evidently going back to around 2011 or 2012 at least. I've looked at a lot of used 4-door Porsches online, and until recently I never saw one optioned with ACC -- not sure why, because I deem it a "must have" item in any car that I buy now, but they seem to be extremely rare items. Perhaps Porsche didn't get it nailed down very well in its early versions. But my 2018 Panamera has ACC, and it's absolutely wonderful in heavy traffic. Good luck with your 2012 ACC... Let us know how it works out.

 

I have the ACC in my 2010 4S, wasn't on my must have list, but now that I have and have used it I would probably add it to the "must have" list of any future cars.
Happily I haven't had any problems with it, been working beautifully - I make sure to keep the dome clean.

 

 

First thing I would check would be the sensor, and make sure to clean it with non abrasive cleaner, mild soap and wet cloth. Residue interferes with the system and can result in turning off. Then start following the wiring under bumper.
Try to see the fuse as well.

I did not plan to have this on my car, but it was on so was a bonus for me.
How do you guys use it? Do you use it in normal traffic? I am very sceptical to trust my car with my car.
Played with it few times, it does awesome job slowing down and even stopping when traffic gets slower. To restart I believe I had to push the gas again to re activate ACC. Then it would continue as before until distance to forward car is reached and then it starts to level or slow down if needed.

Just curious, want to be able to use this well and properly.