Your car's check engine light is often the first indication you'll receive that there is trouble under the hood. This light illuminates when your car's computer detects something out of the ordinary with your engine, exhaust system, transmission, or another critical component. This light is essentially the front end of a larger diagnostic system, alerting you to the presence of one or more diagnostic trouble codes (DTCs).
In other words, your check engine light turning on doesn't tell you much. Sometimes, the computer may be storing a single, relatively minor code. In other cases, several codes may indicate a severe underlying problem with your vehicle. So, what should you do when your check engine light turns on, and how long can you keep driving? Read on to find out!
When Should You Pull Over Immediately?
If your check engine light illuminates while driving, your first step should be to check for other noticeable symptoms. The two most critical issues are oil pressure and temperature. When your temperature gauge starts climbing or you see a low oil pressure indicator, pull over immediately, shut your car off, and wait for a tow.
Misfires are another serious symptom. Misfires usually feel fairly obvious and will cause your car to run roughly and idle poorly. A misfire code will typically cause your check engine light to flash, so never ignore this warning sign. While not as immediately critical as low oil pressure or an overheating engine, you should still avoid continuing your drive if your car is misfiring.
When Can You Finish Your Drive?
If you aren't experiencing any of the symptoms described above, and your car seems to be running relatively well, you can usually continue your drive. Most auto parts stores will offer free code checks, so you may want to consider finding the nearest one and pulling the codes from your check engine light. While these codes won't necessarily tell you the problem, they can help you judge its severity.
Note that even minor issues can still significantly affect your car. For example, a faulty oxygen sensor can lead to incorrect fuel trims, reducing efficiency and potentially damaging your emissions or exhaust equipment. Driving short distances with a check engine light and no other major symptoms is usually fine, but drive gently and avoid long trips.
How Should You Resolve a Check Engine Light?
In nearly all cases, you will want to take your car to a professional repair shop to evaluate your check engine light and determine the underlying cause. While the stored DTCs can provide some clues about the problem, they rarely point directly to the failure. Instead, a trained technician will use these codes as a starting point to find the issue.
Remember that even minor DTCs still mean something is amiss with your car. In some cases, a minor code may be the only symptom of a larger problem that the computer can detect. Allowing a skilled shop to investigate your issue will guarantee you get to the bottom of the problem while avoiding causing more damage to your vehicle.
For more information on auto repair, contact a professional near you.