I am a master diagnostic technician (L-1) and spent 3 years as general manager of a major ECU rebuilder Standard/Blue streak.
I was also the sole technical support for north america fielding up to 40 calls per day from master technicians who experienced befuddlement as to why the 4 different ECUs they put into a car weren't the magic bullet that would fix the car.
I have mastered or have much experience with all brands diagnostics as well as usage of the model scan tools used by the dealerships to these brands.....well....maybe not renault or peugeot.
Hell....I can change a 192 leg processor with a razor blade and a soldering iron as well as component level troubleshoot auto ECUs.
Meanwhile, the dealerships are full of sub-par parts replacers who end up subbing the repair to a local independant shop.
I'm currently designing custom sensors for engine and boost management systems as well as wrenching a 1800hp ford GT but this is piecework and I prefer a regular gig.