Ask The Experts!

What does it mean when the engine symbol lights up on my dashboard while driving?

-Sue from Flint.

That is frequent question that drivers ask and there is not a simple answer, other than the engine symbol is an indication something is going on in a monitored circuit on your vehicle. The check engine light or service engine light is a part of the on-board diagnostic (OBD) system that is a government mandated component incorporated into every new vehicle manufactured. Your vehicle has a number of sensors that monitor the performance of various component parts and send reading to the vehicle’s onboard computer control systems. If the computer receives a signal that is outside of a specified range, it may trigger the engine light to come on. It takes a scan tool programed to the vehicle make and model to read the data provided and diagnose the condition. If the engine light illuminates for a short period of time and goes out that can indicate the condition was intermittent and may not pose an ongoing concern. If the engine light illuminates and stays on through multiple cycles of starting and stopping this can indicate a component failure that needs attention. When using a scan tool to determine the reason the engine light illuminated, a technician reads a stored computer code that corresponds to one of the systems being monitored in the vehicle. This code can, in some cases, pinpoint a specific component failure; however, generally the code leads to a component system that is not performing within specs and the technician must diagnose the reason why.  Either way it takes a qualified technician, trained to perform OBD repairs to know exactly what is causing the engine light to come on. From a driver’s perspective it is helpful to understand that the OBD system can trigger dozens of different codes and every time the engine light illuminates it does not indicate a single failure or repeated failure. This is another reason to have a professional service tech evaluate the vehicle and determine the exact reason and underlying cause for the warning light to appear.