'13 Ford Fiesta - Engine Malfunction, Service Now

So a few weeks ago I got a '13 plate Ford Fiesta. Then I got the "Engine Malfunction, Service Now" warning. I had it diagnosed, and it was an issue with the neutral position sensor, but supposedly that's fine to drive with until I can take it to the garage. The engine malfunction light stopped coming on eventually anyway, but still wanted to get it looked at. Fast forward to today, took it to the garage to have the sensor sorted, started driving home, all seemed fine. The engine malfunction light however remained on, which like I mentioned it hadn't been doing for a couple weeks at least.

Then I broke down on the way home. Accelerator stopped working, car came to a halt from 60. Honestly I was a little panicky so I'm not sure if it was in limp mode, I just found somewhere safe to pull over and make some calls! I'm gonna get it to a garage ASAP but I'd really like some help in understanding what's going on with it. I still have a few days left under warranty to return it but I really like the car itself. Any advice is massively appreciated. (Apologies for any incorrect phrasings/terminology, I don't know anything about cars!)