I am a big fan of people doing stuff to their own cars. It teaches you lots and gives you more understanding on how things work. A copy of WIS is a must if you wish to understand how the systems work and the process'.
Diag is another game. Fault codes are not all the info you need. Codes work from logic and nothing else. What we find is that home mechanics (home fiddlers
) tend to have a go at fixing their car just from the fault code and that can work but often does not. We will then get involved an then wade through the mess which in turn is more expensive. Its a daily problem. As a MB specialist we have access to more information than most and all of this info we use to diagnose efficiently and correctly. We use Xentry (online genuine system) with guided and frank excellent tests. WIS, Star Finder, TIPS, multimeter, scope and the best tool by far, 27 years experience. The tools we have to hand help us get to a result faster than most and with accuracy.
I would be looking at the diag too as a bit of fun and to give you a better understanding of how things work and the connection between the systems before you take it to your preferred expert. I am not saying this to gain work, I am saying it to help. If someone has "had a go" it can create difficulties.
I did a side by side comparison with a launch system, and a generic code reader. Both of them did not pull all the codes that were logged. Xentry did.
Diag is getting harder every year as the cars are getting seriously complicated. They can take hours of work even with the equipment we have. 15% of our work is for other garages, that's a good example of how hard it can be.