MaxiEcu software was created at the beginning of 2009 in Mari company. Its initial name, MaxiTest, was changed into MaxiEcu for commercial reasons. By observing the market of vehicle diagnostic software, we came to the conclusion that there are many expensive programs intended for car repair shops as well as cheap, not particularly useful ones, diagnosing OBD2 system. This is how idea of modular software was born, which, depending on the needs and expectations of the customer, gives the option to choose the modules useful for that particular customer. Selling in a modular system has also influenced the price. For example, we can recommend customer to purchase the Mercedes diagnosis module, and, if he changes his car to Renault, he will be offered the Renault diagnosis module for a small charge.