The Malfunction Indicator Lamp (check engine or service engine soon lamp) will illuminate when the vehicles onboard computer (ECM) has detected the same fault during two consecutive drive cycles or when the ECM has entered fail safe mode.
One function of the ECM is to monitor and detect malfunctioning sensors and actuators, as well as recording emission related diagnostic information. The ECM receives input from sensors, relays, switches, processes the data then generates output signals to control additional solenoids, actuators, and relays to keep the engine and transmission operating smoothly.
When a component fails, the ECM will attempt to compensate by changing the output commands to other sensors & actuators. This is why a driver may not notice any difference in how the engine is running when the Check Engine Lamp illuminates.
It is best to have the vehicle checked promptly. Most Check Engine Lamp diagnostics are relatively straight forward and should be accomplished within the first hour of diagnosis.
There are on occasion, multiple parts that have failed or multiple "fault codes" stored that may require additional diagnostic time to figure out. This is more common when Check Engine Lamp has been illuminated for long periods of time or the vehicle has been running poorly for an extended period of time.
Most common reason for the Check Engine Lamp to illuminate is maintenance neglect. Time and time again, techs find the root cause of many time-consuming and costly repairs stem from what could have been a simple repair.
An ounce of prevention...
Check engine lamp diagnosis range between $49 and $89. We offer more than a simple code scan, some shops do for free to lure in customers. Our job is get to the heart of the problem, provide you a thorough inspection and estimate of recommended repairs.
If the vehicle Check Engine Lamp is only on due to a failed fuel cap, we do not charge for the testing.
We also apply diagnostic fees toward repairs completed here.
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