Stay away from Bosch's scan tools.Once you buy a Bosch scan tool,it is yours with no tech support at all and the reps don't last.The reps quit or Bosch fires them.Vetronix was a good scan tool until Bosch bought them out in 2003.Bosch also owns OTC now.The best scan tool out there is a factory scan tool.It is GM's factory scan tool,only one with a built in missfire graphic and does more.If you encounter a problem with a new window switch for a Chevy Trailblazer/GMC Envoy that does not work,has to be programed with the GM Tech 2.For GMs,I like the Tech 2.You can buy a Chinese built version Tech 2,it is a good scan tool.Don't have updates installed,it will crash and you will throw it away