I was cautious when my BMW would randomly shut off on me while driving. Local dealer said my engine had too much carbon build-up and costing me $600 to clean up the engine. I paid. After few days again shuts off. When I go back to complaint. the same dealer says now I need to replace my turbo for $2,700!! My X5 is a diesel engine, Chris was the technician to get to the root cause of the issue that my BMW's key was not communicating with the car because my battery was dying. It was easy fix that only required me to start using my extra key! He even showed me how to replace key battery. I'm thankful for his diagnosis, that fixed my issue permanently.