Check Engine Lights: Myths And Facts
by Theodore Olson
You're driving along and suddenly your Check Engine Light comes on. What does it mean? Check Engine Light, Check Engine Soon Light, Service Engine Soon Light, Engine Light, Engine Management Light, "whatever" you want to call it, simply means that your vehicle's computer system has detected a problem.
Depending on the year, make, and model, it may be related to the engine, the transmission, even the brakes and suspension. There are literally hundreds of reasons a Check Engine Light may appear. The following questions and answers discussion will clarify the truth about Check Engine Lights...
Service Engine Soon Light FAQ:
1) Can the car be driven? The general rule is: if the Service Engine Soon Light is on, and the car seems to be running ok, you can drive it. However, you should have it checked at your earliest convenience
If your vehicle is running poorly--bucking, stalling, hesitating, or you just don't feel safe, tow it. When in doubt always tow it!
2) The check engine light went out by itself. Is it ok now? Probably not. Check Engine Lights often come and go. Even if the light is out, your vehicle's computer system will retain information that will allow the problem to be diagnosed. To avoid potential long term issues, get it checked out
3) My check engine light stays on. What should I do? If your check engine light stays on constantly, follow the instructions above, under "Can the car be driven?" Don't panic
4) Can I disconnect the battery, or pull a fuse to reset the service engine soon light? Maybe, but I wouldn't. Removing the battery cable or an ECM or PCM fuse may clear the code, but it is not universally recommended in the industry. Most manufacturers advise against it. See the Best Way to Reset Check Engine Light Codes below.
5) What is the Check Engine Light? The Check Engine Light is a warning light for multiple systems operating in your vehicle. In simplest terms, it's like an engine management warning light to alert you of a problem. Just like your computer pops up with an "error message window" saying that something's wrong, your service engine soon light pops up to warn you that it has detected a malfunction: mechanical, technical, software, or otherwise.
6) How to Reset Check Engine Light? This is a great question! I get it all the time. See the guide below.
Resetting Check Engine Light: First, if your Check Engine Light is on, it's on for a reason. The Check Engine Light indicates that your vehicle's on-board computers have stored a fault code. There are hundreds of fault codes, any one or more could be stored in the computers memory. Fault codes are critical for accurate diagnoses of the problem.
Sometimes the fault code points directly to a faulty component, allowing for a quick diagnoses and repair. Other times, the code may only indicate a problem circuit and thus extensive diagnostic procedures may be required.
By resetting the Service Engine Soon Light, it erases important fault code data that turned the check engine light on in the first place. Without this critical information, the root problem can not be discerned.
Unfortunately, there is no "universally" accepted way to safely turn off a check engine light. Even if there was, if the root problem is not addressed, it will come back on.
So whether it's a Chevrolet Service Engine Soon Light, Camry Check Engine Light, Mighty Max Check Engine Light, or a 1993 Thunderbird Check Engine Light, they require individual procedures to diagnose, repair, and reset the check engine light code.
Following is a Safe and FREE way for resetting check engine light codes.
Best Way to Reset Check Engine Light Codes: If you're not interested in diagnosing your truck, SUV or car Check Engine Light, or it's already fixed, and you just want the engine light out, visit any local repair shop. Most shops will have a universal Check Engine Light Code Reader that can quickly and safely reset, and check engine light trouble codes. It should take about 30 seconds.
Note: European models are better off with a specialist, and some older vehicles may require more time.
Here's what to do: Politely ask your local service center (ask a technician if you see one) if they could reset the check engine light with their Check Engine Light Code Reader. They may protest, arguing that the problem must first be diagnosed.
Tell the service representative that you understand fully, and that you appreciate his professionalism. But that you would just like to try resetting the Service Engine Soon Light, and if it comes on again, you'll come back for a full diagnosis.
Be genuine. Service representatives respond positively to sincerity. If the service center wants to charge you just to reset your Service Engine Light, try another facility.
Alternatively, some parts store such as NAPA and AutoZone will reset your check engine light for free. Be wary of "diagnostic ideas" from parts representatives, however. Don't let them sell you any parts to "try" to fix the problem.
IMPORTANT, check engine light repairs can be quite costly given their technical nature. Service centers can easily hide behind complex technical language to inflate the difficulty of your Check Engine Light concern.
About the Author
Theodore P. Olson (Ted) holds extensive certifications from Mercedes-Benz, Toyota, Genral Motors, ASE, and more. Ted is the author of 8 books adn numerous articles on the automotive service industry.