300e

Time for an inspection at a tire and alignment shop. Could be a worn ball joint or control arm bushing. Often they will also cause abnormal tire wear that the mechanic can "read". Pulling is never a good sign. It could be just an alignment problem but if it shows up suddenly, it is usually something that can become serious if it's neglected.

More expensive to wait until something breaks. Without knowing the recent history, it is entirely possible it just needs an alignment. The two angles that affect pull are camber and caster. Camber is the tilt in or out on top as you look at the tire from in front of the car. The tire will want to pull in the direction it's leaning. If the misalignment is real severe you will see much more wear on the inner or outer edge of one of the tires but it will usually be smooth. Caster has to be visualized. Think of the fork on a bicycle and how it goes forward as it goes down. Normally all that is important is it is the same on both sides so they balance each other out. If one side is higher, it will pull toward the center of the car harder than the other tire thus creating a pull. Normally that angle won't change on its own and normally it has almost no affect on tire wear, however Jeeps and Mercedes call for a caster setting about four times higher than other cars. That makes the tires lean into a corner much more than normal so there can be some wear on the edges of the tires. You could also just have a tire pull and not an alignment problem. That can be identified by switching the two front tires to see if the car pulls the other way. If it does, rotate them front-to-back and just leave 'em like that if the pull is gone.