Inner Cooler pump goes bad, small oil leaks around valve covers, crankshaft position sensor fails, relay control module has poor solder joints, so it will fail. You need to do your homework and read thru the threads on here. There are sticky notes about how to's on you fixing these problems yourself. Whomever is doing the diagnostics on this car better know the car or you are wasting your money. Most dealers know absolutely nothing about the car, and Mercedes won't work on them. $12K is a steal.....btw...all the above mentioned problems WILL happen sooner or later...important to know and understand their fixes. All can be done by you for under $500.00...a dealer, 10x that amount if they can figure it out...good luck