Automotive computers repair where, who ????????????

There are those who say that they are already repairing the time of time the mechanics are in the middle of the problem.
We see workshops with simulators, several scans and it is seen that if they have knowledge but the computers are not well repaired, what happens? There is no sufficient information about them, diagrams or specifications,
I have not wanted to ask for them online for fear that they do not answer me with the guarantee for how expensive they are.
I seek to have the service in my city so as not to wait long for the pressure of customers who run out of their vehicle in my city of Mexico but I can't find it.
I know that repairing a computer should not be simple there are very complex components in it, there are memory areas, injector drivers, sensor input signals, actuator outputs, etc.
And I know that this is not only a problem in this country but in all of Latin America since without that computer, whether engine, body, ABS, etc. The vehicle on many occasions is groped and becomes technological garbage.