Hi, when I attach my erde trailer and select mode, Eco is dulled out and can not be selected, any idea why? But in individual it can still be customized and must be working as it displays E on the maxidot and the car will still coast.

Thats the Trailer Stability system stopping the Eco Drive mode working. Its suppose to.

 

Free wheeling/coasting downhill with a caravan attached isn't something I'd wanna try, granted a small trailer probably wouldn't cause an issue but, having towed some large loads, I'm happy to let the software do its thing