I have an '08 Mercedes SL55, and a scangauge. The scanner cost $170. The codes are read through the standard obd2 port. It wouldn't be surprising if the deal

I have an '08 Mercedes SL55, and a scangauge. The scanner cost $170. The codes are read through the standard obd2 port. It wouldn't be surprising if the dealerships have fancier diagnostics available via $40k machines, but they're in no way crippled from standard service.