* The problem that caused the code to be set in the first place is still present. This is the most common reason why an engine light will come back on after it's been cleared. If the problem isn't fixed, the engine light will eventually come back on, even if you keep clearing the code.
* The code was cleared incorrectly. If you didn't follow the proper procedure for clearing the code, it's possible that the code will come back on.
* There's a new problem with the engine. If the engine light comes back on after you've cleared the code and you're sure that the problem that caused the code to be set in the first place has been fixed, it's possible that there's a new problem with the engine.
If your engine light comes back on after you've cleared the code, it's important to have the car diagnosed by a qualified mechanic as soon as possible. Driving with an engine light on can damage the engine and lead to costly repairs.
