The bearing all depends. Im not familiar with what kind of car you have. If you need new axles or spindles it is mor involved & expensive. If just bearings, you can do it yourself, if you know how, and if you take it in it could be a couple hundred. For my car the bearings are expensive, but for my 89 GT they were cheap. As far as your check engine light... thats kinda weird. It sounds like something is shifting with the braking and the turning. I suppose you could be losing oil pressure because you dont have enough oil (if it's burning or leaking), but I would think the oil light would come on not the check engine light. It could be some other fluid that's low, or some electrical connection that's briefly losing it's ground or connection all together. Unless you can notice something else happening with the engine light coming on, you prob have to check your car for codes. I thought you could do this on older escorts with an ignition trick, but Im not sure. Otherwise you have to have a mechanic hook a device up to your computer & pull the codes. You could buy a reader, but theyre expensive. Some parts shops will let you use theirs for free, but I'd call ahead to ask. Anything going faulty will be stored until you remove your battery, and it should be specific enough to help you.