If vehicles had brains, the ECM would be the perfect fit. Depending on the vehicle and the year of manufacturer, the unit is called the TCM or ECU. It is a major component in any car. Basically, it is the main computer system for the vehicle which monitors the drivability systems as well as the performance of the engine. There are sensors in the engine which pass information to the ECM which is in turn used in calculation and tuning engine fuel and spark for all the parts to perform powerfully and efficiently. Given how critical the part is, you will not be able to use the vehicle if it fails. With knowledge of what a failing ECM looks like, it will not be that difficult for you to know what to do when it comes to that. You should not ignore a check engine light because it means there is a problem. A simple test is used in checking the error code. Once this is known, fixing the vehicle will not be a problem and you will go back to using it soon.
It is also very easy to tell when the ECM is not in good shape based on the engine behavior like misfiring or stalling. A faulty computer system might also be the cause of the problem but this is mostly an intermittent problem. The occurrence and disappearance of these signs might not follow a given pattern. Also, the pattern might not be an indicator of how severe they are. There will be issues with how the engine is performing if the ECM is not in a good condition. It is the ECM that controls the timing of the fuel settings. You may face unexplained fuel efficiency drops or even the vehicle struggling in shifting. If a properly functioning vehicles takes a turn for the worse, you need to call your mechanic as soon as possible so that you can get an idea of what is happening.
You can also gauge the status of the ECM based on how fast the vehicle starts when you turn on the ignition. You expect the vehicle to give you a hard time in starting or even fail completely if the ECM system is faulty. If the system is damaged to the point where only a replacement can save the vehicle, you have to do your part in making sure that things do not go south. Every ECM is unique to the particular vehicle which means you have to get the right number in order to tell your mechanic what has to be installed. You should also make sure the manufacturer is renown in manufacturing the best spare parts because it is the only assurance that you will not be back in the market searching for the same product in the near future.