Q: do i need to take my car to BMW for an oil change or brake fluid flush

In regard to your question, the criteria of relevance insofar as "who" should work on your car is simply that the person you select is appropriately trained, skilled, as knowledgeable as possible, knows how to follow instructions, and is conscientious, that is maintains and repairs your vehicle as if it was his or her own. Some mechanics at shops or dealers have these qualifications and are worth working with, however, due to the economics of shops, in particular the high overhead and high profit margins, the costs to consumers are often economically irrational. The lowest cost and best results, often because the service is personalized, will come from mobile services so long as the mechanics are certified, as they are at YourMechanic. The particular services you are inquiring about, namely an oil/filter change and brake system flush are common and routine services and thus offer particular cost savings on a mobile basis. As you get into more complex services, such as brake system refurbishment, suspension repairs, and so forth, the advantage of "personalized" mobile service becomes even more apparent because shops tend to cut corners and, at the same time, they will often buy the cheapest "aftermarket" parts possible, all the while marking them up by the maximum they can get away with. At YourMechanic, the customer is informed of the differences in OEM versus aftermarket parts, because the mechanic who actually does the work is almost always right there with the customer to personally convey that information, as requested. With regard to the check engine light, if that light is indeed illuminated on your vehicle the service to request is a check engine light diagnostic. If you have further questions or concerns, do not hesitate to re-contact YourMechanic. We look forward to serving your automotive maintenance and repair needs.