What does the Check Engine Light mean
The reasons why thecheck engine lightcomes on a vehicle's dashboard are multiple and varied. The check engine light or malfunction indicator light (MIL) is the way a vehicle's computer communicates with the driver. The computer turns on this light to indicate that trouble with a controlled system has been detected. More than that, though, this warning system is also a way for a car mechanic to focus on a particular set of components or system(s) when trying to fix the problem before it may turn into a serious issue. Thus, the computer is not only able to alert of a potential problem, but also provides more specific information about the nature of the problem.A vehicle's warning systemA car's computer is capable of controlling a few or several systems at the same time using a series of sensors and actuators. The number of systems under control depend on the specific vehicle make and model. However, there are a number of systems generally managed by the computer, mainly emission control units:- Exhaust gas recirculation (EGR) system- Air injection system- Engine management system- Catalytic converter- Heated air intake system- Positive crankcase ventilation (PCV) system- Evaporative emissions control system- Carburetor control systemHow the computer stores information on a potential malfunctionA car's computer comes equipped with a set of working parameters for each component and electrical circuit under control. Therefore, whenever one of these components or circuits deviates from its pre-established working parameters, the alert system is activated and a glowing check engine light appears on the dashboard. Each one of these events has a corresponding trouble code identifying the nature of the problem.The computer identifies each trouble event it encounters and stores this information in its memory. This is known as theOn Board Diagnostic(OBD-I or II) system. This code is an alphanumeric line that may look like this: P 0141, indicating whether this is a standard trouble code (P), which system is involved (0-1), and the potential component or circuit involved in the fault (41). A standard trouble code chart will help in determining the nature of the problem.Retrieving trouble codes from computer memoryAutomotive mechanics retrievetrouble codesevery day as part of their troubleshooting strategy. In fact, it is possible for home mechanics to retrieve this information as well from their own vehicle using an automotive code reader or scan tool designed for this purpose. These tools are available in most auto parts stores and have become a great help in car repair and maintenance. Therefore, a scan tool can not only help in pinpointing the reason why a check engine light or MIL illuminates, but also in diagnosing the health state of engine management systems when maintenance service is due as well.Vehicle manufacturers are incorporating a growing number of systems under engine management. This strategy incorporates more than one computer under control of a central unit capable of informing the driver of almost any potential problem like an underinflated tire. Therefore, drivers are seeing a greater number of reasons why the check engine light comes on. And the reasons will keep growing as new vehicle models with newer technologies hit the market. This will not only allow a car owner to keep the vehicle running at optimal conditions but also avoid damage to particular systems before they can turn into costly repairs.
