As above , you need to be as agile as a monkey on the new vehicles , there is just no room . Also you will need sophisticated diagnostic equipment as the vehicles share the same concept but still differ greatly from model to model in degrees of sophistication. Even run of the mill stuff like tow-bars are no longer straight forward unless you fit the manufactures dedicated harness's , if available.
And not fault all codes are available, some faults need to be referred to the manufacturer to be reset or reprogrammed.
An interesting job though , but can be very taxing.
Once you have been around the block and get to know the models the faults are recurring to a degree.