Customer purchased used transmission from us for 2002 X5 3.0L, installed it at some mechanic shop and justified it by relying on CO's BMW of Fort Collins diagnoses. Then we got a call from him saying that same problem is there and he wants to return it, we offered an exchange but also to bring the car to us for evaluation. So once vehicle got here diagnoses showed throttle body to be erratic in it's readings, swapping $40 part and diag time fixed the car right up. I cannot understand how big reputable dealerships can charge people to diagnose a problem with only hooking up scan tool and pulling codes then guessing the next steps just by some suggestion in their step by step problem solving software or any other "certified guess" practice they rely on.