Application of a lot of modern technological solutions in every car manufactured in present times contributes to increased safety of driving and easier defect diagnostics. One of the main elements, which is considered as the proverbial ‘heart of the car’ is without doubt the engine control unit thanks to which our car will function correctly. Thanks to this small and at first sight inconspicuous device, all the systems that are present in our vehicle work together properly. In the event of a failure of the controller we can replace it with a new one or possibly try to repair this element.