First off most of our customers at 5-Star Auto Repair & Exhaust of Lexington refer to the light on the dash we are referring to in this article as a Check Engine Light. Some also refer to this light as a "SES" Service Engine Soon, or "MIL" Malfunction Indicator Light, all of which are the same thing. Occasionally this light is confused with the Maintenance Indicator Light which is a reminder light for Factory Scheduled Maintenance. Reasons for the Check Engine Light to come on can vary from simple issues such as a Loose Gas Cap to more complex issues such as a shorted wire, failed ECM/PCM, or the most difficult an intermittently failing electrical solenoid. All modern vehicles are computer controlled. Most have multiple computers that work in sync with each other to make the vehicle operate, this also involves a large number of sensors monitoring what the engine is doing and how it is running. sometimes these sensors fail and will cause the Check Engine Light to come on. Sometimes the sensors are working properly, and a related part in the system they monitor has failed causing the light to illuminate. For example your vehicle has high mileage and the Check Engine Light comes on, you take the vehicle to a parts store they use a code reader and say you have a bad Oxygen Sensor, and they sell you the sensor. You install or have the sensor installed but the light comes back on. Most likely in this case the sensor wasn't bad. So you take the car to a repair facility they use diagnostic equipment to find your Catalytic Converter is failing, which is the actual cause of the sensor causing the light to come on.
It is my professional opinion you should always have a certified technician diagnose your vehicle rather than a part store guess whats wrong. What Does It Mean When The Check Engine Light Flashes On And Off? Typically this indicated a Catalytic Converter damaging event. Most commonly a Cylinder Misfire, this is usually accompanied by rough running "shaking" and poor performance. Is It Safe To Drive With The Check Engine Light On? Honestly taking into account yourself, the vehicle, and the environment, any time the check engine light is on one of these can be damaged. How Do I Turn My Check Engine Light Off? I don't recommend turning the light off by unhooking the battery or having a parts store turn it off. I recommend having a reputable shop repair the issue, and then clear the light afterwards. A proper test drive or automated vehicle self test can be performed to ensure the repair is successful. In closing 5-Star Auto Repair & Exhaust of Lexington is happy to assist you with any Diagnostic problems you may have.