Why is my Engine Check light on AGAIN?

 All modern vehicles have a computer or the ECM (Electronic Control Module) that controls the engine operation. The main purpose of this is to keep the engine running at top efficiency with the lowest possible emissions. With today's strictest emission regulations it's not very easy to achieve - the engine needs to be constantly and precisely adjusted according to various conditions such as speed, load, engine temperature, gasoline quality, ambient air temperature, road conditions, etc. Today's cars have much more electronics than in early days - there are a large number of various sensors and other electronic components that help the engine computer or ECM to monitor all vehicle emission-related systems. When the computer senses that there is a problem with any emission-related system or component, it stores the trouble code(s) in the ECM memory and lights up the "Check Engine" symbol to tell you that there is a problem and your car needs to be looked at. Depending on the severity of the problem, the light will be either lit continuously or flashing. If the engine check light or symbol is flashing, immediate action is required in order to prevent damage to other components and the vehicle should not be driven under such condition and should towed to the dealership.  The technician at our dealership then will hook up the scanner to the car computer, retrieve the stored code(s) and initiate system testing and fault finding procedure. More than a hundred different codes are possible and can trigger the “Engine Check” light. The code itself doesn't tell exactly what component is defective - it only says what engine parameter is out of normal range. The technician will have to perform further testing to pinpoint defective part.

Fuel quality, lack of regular service and poor driving habits can also have a significant impact on engine drivability and performance.

Reoccurrence of a lit “Engine Check” light may or may not be the same cause as on a previous visit, as some problems are obscured by other fault codes depending on their precedence.

 I hope this will give you a better understanding about this pesky light.

 Best Regards,

Hermann Riegel   Shop Foreman